Help me diagnose a heating fault.

[ProDave]

This is a neighbours heating system.  I don't normally do "plumbing" for others, but I am too nice to say no.

 

House built about 15 years ago, UFH downstairs, radiators upstairs, driven by an oil fired Aga.

 

Initial problem some rooms not getting warm.  But problem No 2 today that got me round there, water dripping through a ceiling.

 

The dripping water problem is an odd one. Above and just to the side of the leak it a hatch with the pump and motorised valves.  All dry there.  so on owners instructions I cut a hatch in the ceiling.  Just a single pipe runs across above there and that pipe is dry.   By the time I mopped up, it is no longer dripping, so that one is "pending"

 

So onto the heating.

 

All motorised valves are opening, hot water is flowing to the HW tank, and UFH but the pipe to the radiators remains cold.  All radiators have TRV's and all turned up to maximum.

 

At the UFH manifold, HW is arriving at the manifold and the pump is running. All actuators seem to be opening, but very little water is flowing, each loop the flow pipe is warm but return pipe stone cold.

 

Now onto the "clue"  If you look in the sight glass of the flow meters on the manifold, you see nothing. It is completely brown, you cannot even see the "float".

 

So my guess is the whole system is completely gummed up with rusty crud and needs a complete flush out.  That is needed anyway even if it turns out there are other faults.

 

The house in on borehole water, which (unusually for these parts) is very hard water as there is a seam of limestone running under here.

 

Part 2:

 

How do I flush it?  

 

UFH is easy, water hose to supply manifold, drain hose to return manifold, run water through each loop in turn until it runs clear.

 

But how do you flush all the radiators?  What's the usual procedure? 

 

 

 

[Onoff]

Power flush with the right kit?

[Nickfromwales]

Is there a magnetic filter fitted? 

Have you closed all the ports bar one and see if that gets circulation ? 

I’d say the first port of call would be to change the manifold pump and then re-evaluate. 

Try opening the TMV to its highest setting and see if that gets things moving. If so, it’s the TMV that’s sludged / seized. 

The weir gauges are easy to clean and give worrying indications ( false ) that the system is heavily corroded / sludged up. 

If you isolate the manifold and blow the pressure off, most clear viewing caps just simply unscrew. Clean and replace with a bit of silicone lube on the threads and you’ll be able to view whatever is, or isn’t, going on. 

[ProDave]

The above will diagnose what is going on with the UFH.

 

But what about the rads?  Motorised valve open, all TRV's on max, seemingly no flow at all.

 

Bleed all radiators for sure (didn't have my key with me today) but what, apart from sludge would stop all flow through the rads.

 

Pipework is a mix of 22mm copper at the motorised valves, swapping to some variant of plastic pipe to manifolds somewhere, emerging at each rad as something like 10mm copper.

 

Not seen a magnetic filter anywhere.

[Temp]

Double check the actuators... I had a problem where the wax actuator appeared to open (the button on top came up) but the pin was stuck down so no water was flowing. Removed head and pulled gently on the pin and it opened.

[Temp]

I had a rented house once with rads full of sludge. Just connected a hose to the drain and ran it outside to a man hole. I emptied, refilled and ran the heating a few times to clean it out. Mine was vented but yours is probably pressurised. So after connecting the hose and opening the drain valve you may need to open the filling loop valve to force fresh water in and old out. After its all working remember to put corrosion inhibitor like  Fernox F1 in the system. May need more than a few bottles to get the right concentration.

[ProDave]

Well there is a new twist.

 

Just had a phone call, leak above the ceiling in a different place.  So I am going back again.

 

My bet is shot expansion vessel and non working blow off valve,  over pressurising and causing random leaks.

 

I will ask when it was last serviced 

[Jeremy Harris]

5 minutes ago, ProDave said:

I will ask when it was last serviced 

 

When we put our old house on the market, I had the boiler and heating system serviced first (knew we'd get asked about it by the solicitor, anyway).  That was in July.  The chap that came out said he was really surprised to be asked to service a system in mid-summer, as everyone usually waited until the system failed to work when they turned it on in the autumn before calling him out.  The service was cheaper, too, as they were offering a 20% summer discount.

[epsilonGreedy]

1 hour ago, JSHarris said:

When we put our old house on the market, I had the boiler and heating system serviced first (knew we'd get asked about it by the solicitor, anyway). 

 

 

I have always been suspicious of the concept of servicing a gas boiler, it is not like a car with things that require regular topping up or tweaking.

 

The boiler in my new build house ran without any care or attention for 7 years at which point I got it serviced mainly due to peer pressure from others at work. I watched the service, it was observational looking for negatives then the clot, who had complained to me about his bad back and the cost of his individual CORGI registration rammed the case back on and clipped a case ventilation fan vane. For the next 7 years the boiler sounded like a jet engine and then started to regularly break down, year 8 it was a circuit board, next a valve deep inside the boiler then the main circulation pump.

 

I appreciate that the jet engines on a commercial airliner warrant routine observational maintenance checks but I doubt "boiler servicing" will spot pending failures or extend the working life. 

[Jeremy Harris]

17 minutes ago, epsilonGreedy said:

 

I have always been suspicious of the concept of servicing a gas boiler, it is not like a car with things that require regular topping up or tweaking.

 

The boiler in my new build house ran without any care or attention for 7 years at which point I got it serviced mainly due to peer pressure from others at work. I watched the service, it was observational looking for negatives then the clot, who had complained to me about his bad back and the cost of his individual CORGI registration rammed the case back on and clipped a case ventilation fan vane. For the next 7 years the boiler sounded like a jet engine and then started to regularly break down, year 8 it was a circuit board, next a valve deep inside the boiler then the main circulation pump.

 

I appreciate that the jet engines on a commercial airliner warrant routine observational maintenance checks but I doubt "boiler servicing" will spot pending failures or extend the working life. 

 

 

Servicing is probably a bit inaccurate, as the two key aspects are making sure the boiler is still safe (emissions from boilers and explosions caused by them do still kill people every year) and making sure that the hydronic stuff is all OK (inhibitor has a finite life, corrosion products build up in the filter and need cleaning out, PVs need checking, etc).

 

Most of the time a modern gas boiler won't need anything doing to it, but as CO has no odour, and can build up to lethal levels undetected (unless the house has a CO alarm) then ensuring that the boiler is still burning cleanly, and that all the covers are still properly sealed, is a useful safety check.

 

I used to clean out the filter on our old CH system every year, and add a bit of neat inhibitor into the empty filter housing when replacing it.  Every time I did this the magnet in the filter came out covered in black crud.  Leaving this to circulate or settle in the base of radiators would eventually cause blockages, hence the need to clean the stuff out regularly and make sure the filter carries on working.

[PeterW]

11 minutes ago, epsilonGreedy said:

it is not like a car with things that require regular topping up or tweaking

 

So that assumes it’s not a system boiler where the expansion vessel requires repressurising then ..? Or the FGA values checking to ensure the mix isn’t out due to needle wear in the metering head... or the CO level isn’t off the scale due to blockage in the inlet air vents ...

 

Circ pumps run much better in clean water with less crud in them, and gas valves fail due to the fact most are metering valves that move constantly based on gas pressure and heat demand ... servicing is no bad thing !!

[epsilonGreedy]

4 minutes ago, JSHarris said:

Servicing is probably a bit inaccurate, as the two key aspects are making sure the boiler is still safe

 

 

You might have detected I have a downer on the whole Gasafe/Corgi industry and view the extraordinary fees charged as a symptom of longterm of failed Government policy that for 30 years has produced legions of unemployed Business Studies graduates with £50k of loan debt and a shortage of qualified trades because of the willful destruction of vocational education.

 

The net result is that an enterprising GasSafe fitter will retire with a greater networth than an NHS brain surgeon.

[Jeremy Harris]

I'm not sure that all people working in the boiler servicing industry can be just lumped together in this way. 

 

IIRC, I paid about £70 to get our boiler and heating system serviced, and that included safety checks on the gas cooker and a gas open flame fire.  The chap took around 2 hours to do the work, including cleaning the mag filter and adding inhibitor, so it wasn't outrageously expensive, especially in the context of certifying that the items were safe. 

[epsilonGreedy]

8 minutes ago, PeterW said:

servicing is no bad thing !!

 

 

Is gas boiler servicing economically rational? My point is not technical, I am observing that in the UK a competent GasSafe person is such a rare commodity the cost of their time is bizarre in relation to the task performed. The last GasSafe person I employed was complaining about the cost of horse feed and the £22k invested in the 2 acre paddock to keep his wife and daughter saddled up.

 

My one and only boiler service seemed to precipitate failures. It was 12 years ago but I do not recall a check of the quality of the circulating water and has @JSHarrisillustrates this is definitely within the scope of DIY heating system maintenance checks equivalent to looking at a car dipstick on a Sunday morning three times a year.

[ProDave]

Okay just back from there again.

 

Since putting the system pressure up to 1 bar (it was about 0.5 bar) yesterday, everything has started working, radiators and UFH.

The pressure vessel for the heating is fine, it's bladder is holding air and the blow off valves both work.

I bled the radiators. There was no air, and the water that came out was clear, that blows the gummed up with crud theory out of the water.

 

The leaks I have determined are from the hot or cold water.  I checked the borehole system (in a shed) and that is sitting at just under 3 bar. I had thought the pressure switch might have failed and it was over pressurising.

 

So the mystery to find and fix is 2 leaks that started on consecutive days. Too far apart to be just 1 leak and water tracking along a pipe. So apart from cutting holes in the ceilings to find and fix it, the question remains why have two pipes decided to leak?

[epsilonGreedy]

2 minutes ago, ProDave said:

So the mystery to find and fix is 2 leaks that started on consecutive days. Too far apart to be just 1 leak and water tracking along a pipe. So apart from cutting holes in the ceilings to find and fix it, the question remains why have two pipes decided to leak?

 

 

Condensation resulting from the recent change in weather as we switch into autumn? Has something blocked ventilation of the attic space? Or change in householder habits, e.g. air drying of cloths in the room below. 

[ProDave]

No definitely a water leak.  Turn off stopcock and after about 5 minutes the drip stops (there is wood fibre board up there acting like a sponge).  Then turn the stopcock back on and after a few minute the drip starts again.

 

Most pipe is copper, some soldered, some with pushfit connectors, but the runs under the floor seem to convert to a white plastic pipe, I have not determined the make yet.

[Vijay]

2 hours ago, JSHarris said:

I'm not sure that all people working in the boiler servicing industry can be just lumped together in this way. 

 

IIRC, I paid about £70 to get our boiler and heating system serviced, and that included safety checks on the gas cooker and a gas open flame fire.  The chap took around 2 hours to do the work, including cleaning the mag filter and adding inhibitor, so it wasn't outrageously expensive, especially in the context of certifying that the items were safe. 

 

I agree that they aren't all bad, but finding one you can trust seems to be a rare thing. I only know of one around who works local. A mate had a problem with his combi which was obviously the diverter valve. The heating engineer even told him so, but said he needed a new boiler at £2200 as the part was too expensive to change and if that had gone, then other things would soon fail. You can get the diverter for £80 or the service kit for £15. I know for a fact it's less than an hour to change the part. There's just more money in charging someone a grand odd labour to install a boiler which is just wrong!!

[epsilonGreedy]

22 minutes ago, Vijay said:

I agree that they aren't all bad, but finding one you can trust seems to be a rare thing. I only know of one around who works local.

 

 

I have called in two recent years, both of whom I would rate high in terms of competence and trust. The problem is their financial expectations which is £150+ as they step though the front door. It is a market distorted by government policy and incompetence.

 

Even though I will be fitting an LPG boiler I intend to design gas fitters out of the rest of my life so that no GasSafe person will ever be let into my property. Looking at the going rate for comprehensive central heating maintenance cover we are talking about £250 to £400 per year. Many examples in the press quote £700+. At my age that would require about £15k being placed in an annuity to fund index linked central heating maintenance cover for the rest of my life.

[PeterW]

6 minutes ago, epsilonGreedy said:

Even though I will be fitting an LPG boiler I intend to design gas fitters out of the rest of my life

 

Fit an ASHP... job done ... 

[Jeremy Harris]

6 minutes ago, epsilonGreedy said:

Even though I will be fitting an LPG boiler I intend to design gas fitters out of the rest of my life so that no GasSafe person will ever be let into my property.

 

Not sure how you can do this legally.  It's an offence for anyone who isn't a recognised competent person to connect, maintain, adjust etc any gas appliance.  Doesn't matter if it's LPG or mains gas, the same regulations apply.  As well as breaking the law by DIY'ing a gas installation, I strongly suspect that there may be insurance implications in the event of a fault that causes a claim.  If there was an accident and someone was injured then prosecution would be inevitable, I'm sure.

 

Although both gas and electrical installations must comply with regulations, failing to get an electrical installation inspected and tested is just a breach of regulations that rarely causes a criminal prosecution.  Failing to get a gas installation properly installed, inspected and tested is almost certainly a criminal offence, specifically a breach of the Gas Safety (Installation and Use) Regulations 1998: https://www.legislation.gov.uk/uksi/1998/2451/made

[epsilonGreedy]

7 minutes ago, JSHarris said:

Failing to get a gas installation properly installed, inspected and tested is almost certainly a criminal offence, specifically a breach of the Gas Safety (Installation and Use) Regulations 1998: https://www.legislation.gov.uk/uksi/1998/2451/made

 

 

I can see two different interpretations of that, the worst is that knowingly never inspecting or servicing a gas boiler that was installed and certificated correctly eventually constitutes criminal behaviour. Is that the case?

[Jeremy Harris]

2 minutes ago, epsilonGreedy said:

 

I can see two different interpretations of that, the worst is that knowingly never inspecting or servicing a gas boiler that was installed and certificated correctly eventually constitutes criminal behaviour. Is that the case?

 

There's only one interpretation  of the regulations, and that is that any gas appliance must be installed and maintained by a competent person.  It may be offence for anyone that's not competent to install, modify, maintain or adjust any gas appliance, within the bounds of the aspects of that appliance that fall within the regulations.  In general terms, the regulations cover all of the gas pipe work, connections, valves etc that are not intended to be touched by the user, plus the flue, air vent, combustion controls and all electrical or electronic components associated with safe operation of the appliance etc (it's an offence, for example, to change the circuit board, or any sensor that controls the combustion process yourself).  You can usually maintain the non-gas or combustion parts of an installation yourself, so things like water circulating pumps, filters, radiator valves etc.  At a push you might still be alright re-charging a PV, or perhaps replacing one.  On the electrical side I think that wiring up an appliance is OK (but is covered by BS7671 anyway), as is wiring up controls like room thermostats or a programmer.

[SteamyTea]

Re the CO sensor issue with gas boilers, it is a pity that it is not mandated that the boiler is fitted with one at manufacture.  Then a warning for when it needs changing, and auto-shutdown if it throws a fault or goes too long unchanged.

Now I know that some people will find a way around it, but most wont.

CO sensors are cheap, as is a logic control, so why is it not done.  Cars have a lot more safety systems that run reliably for years, and cars a re cheaper than they have ever been (in real terms, not individual terms).

While they are at it, they could mandate that all electrical meters have an isolator too.  Another simple thing to improve safety.

Edited October 4, 2019 by SteamyTea

[epsilonGreedy]

11 minutes ago, JSHarris said:

There's only one interpretation  of the regulations, and that is that any gas appliance must be installed and maintained by a competent person.  It may be offence for anyone that's not competent to install, modify, maintain or adjust any gas appliance, within the bounds of the aspects of that appliance that fall within the regulations...

 

 

Ok but I was thinking of a more specific case. If a householder ignores a central heating boiler for 25 years and never arranges a maintenance inspection by a qualified pro would that constitute an offense?