To give some background………I have an 11 year old Worcester Bosch Greenstar 24i system boiler with the boiler thermostat set to about 65c and a 30 year old vented HWC with the cylinder thermostat set to about 55c.  We have sufficient hot water for our needs even though it never heats to the cylinder thermostat setting, generally the temperature at the taps is about 50c.  The issue I am having is that in a one hour DHW heating cycle I have noticed that the boiler fires for about 20mins in total in the one hour period, the rest of the time the burner is off but the pump is continuously running. BTW I have an ABV installed which I have checked to make sure it isn’t activating.

A typical cycle is…..Schedule on, boiler fires, after about 15mins the boiler turns off the burner having reached the boiler set temperature, pump continues to run, about 35mins later the boiler turns the burner on again (flow temp at approx 48c), after about 5mins the boiler turns the burner off having again reached the boiler set temperature, about 5mins later the schedule turns off and the pump finally stops.

Clearly the HWC is unable to absorb all the heat from the boiler resulting in a low deltaT of about 6c between boiler flow and return. Lowering or increasing the boiler set temperature by a few degrees either way makes no difference, adjusting the flow restriction valve on the HWC return makes no difference and Worcester Bosch tech support tell me the boiler can not be range rated so am I just stuck with a poor performing boiler? I know this issue will go away once the heating season is back but I am wasting electrical energy in the mean time due to the pump running continuously during the “ON” schedule.

Any suggestions on what if any improvements I can make would be appreciated, other than to scrap the boiler and buy a lower rated one.

Thanks

The leveller has effectively cemented the pipes into position. Is this OK or unwise ?

LVT will be going down on the floor.

Possible issues - Will this make it problematic to remove and reinstall the rad because of lack of play on the pipes ? Will the heat from the pipes crack the leveller or effect the LVT ?

I have 4 new rads that were installed downstairs as part of our new heating system using plastic press fit pipework (copper upright stems). Two modern panel type radiators - one medium - one small, and then two old fashioned style column radiators - one 4 column medium size, one 3 column medium size. Builders plumber came 3 times to rebalance them and couldn't get tham all fully up to temp, eventually resorting to going behind my back to turn the boiler temp up to 65C and then claiming he had fixed it (not).

Have had suggestions it is likely a pipework/flow problem and column rads take more flow to drive them.

Replacing all the pipework not an attractive option as much of it is now under glued down boarding. I do have two lengths of empty conduit going back under the floor to the boiler location that were put in in case of future desire to extend the underfloor heating. So if an additional pipe loop was created via this conduit to take a column rad off the current loop, and put it on a second loop of its own - is this going to provide a solution to the problem ?

It's a fairly well insulated and airtight new build, and the spreadsheet shows I need < 2kw.

I'm planning to fit a heat pump, with 1 or 2 kick space heaters (fan coils) in the lounge / kitchen and a towel radiator in each of the bathrooms upstairs.

I was thinking I could have 2 zones, one with a (portable) room stat for the kick space, and the other with smart TRVs that can switch the heat pump.

I've spent ages on the Tado website, but still not sure that it could do what I want.

There must be others.............

Thanks for looking,

Cast iron radiator centre are a supplier that seem to be competitively priced, if not one of the cheapest suppliers on the market.

A potential catch which I am trying to resolve is the accuracy of their claimed performance (watts).

I asked AI to compile a table and it illustrates as I thought, that CIRC claim their sections put out ~25% to 30% more heat than most other brands.

As these sections are pretty much the same design, and I imagine are produced from same material, across all brands it seem like a claim worth verifying.

Has anyone ever had the similar query?

The heating system will be ASHP so I'm keen to match the respective heat loss figures for each room accurately and Obviously I don't want to end up with undersized rads. .   

3-Column Cast Iron Radiator Output Comparison (~745-750mm Height)

Per-Section Output @ ΔT50

Heating graph shows a fairly normal, dark winters day:

When its sunny the thermal gain is good enough to help heat the room quickly:

I've no more ports available on the manifold, and the days of taking the floor up to feed pipes through is now gone, however I've had a thought, and wanted to know whether it was feasible...

So the boiler is on the wall right next to where the kitchen is, and i'd wondered about drilling two holes through the wall and tapping into the 22mm flow feed (which goes to the manifold), and making it another bypass radiator to go with bathroom (though this goes via manifold). Had a look and found some 22mm valves, with a 3/4" inlet fitting, but radiators with this seem few and far between, will keep looking.

Boiler Flow Pipe > Small Rad > Flow Pipe to Manifold > to rest of rads > and then Return back to boiler

Another idea, which would give out much less heat, would be to make a radiator from 22mm copper pipe.

What I want to know is basically is this feasible? I'm thinking it could impact flow rates to the manifold hence why i've gone looking for large bore fittings? Any one ever done anything like this before?

Radiator sizing would have an output of between 1000 and 2000 BTU, just pinching a small amount of energy on its way to the rest of the bungalow.

Just to add current flow temp is set at a max of 46C, but my Tado optimises this based upon the weather, and it generally sits around 42/43C. Of course this could be turned up which would help, but i'm trying to future proof in case I have to have an ASHP at some point.

Thoughts?

Cheers

Mike

Hi there,

We're looking to replace our CH system from the Jurassic era. This will involve installing a new combi boiler (to replace old gravity fed boiler) & 8 double radiators (replacing the old single panel ones). As the system is so old (i'd guess >30yrs at least, probably 40+) we imagine it'll need a whole new pipework system (especially as the combi will be in a different location), so plan to replace the old pipes

One plumber mentioned using MLCP - has anyone any experience of this type of pipework? While it's cheaper & more flexible, i wasn't sure if anyone had concerns over durability and if the connection joints degraded over time with systems like a combi?

We'll probably end up with copper pipes & soldered joints, but always worth asking around before making a choice - Pros & cons are always worth thinking about up front!  

Thanks for your time & thoughts

Shadow

it is an old oil boiler( not combi)  

I have filled the system to 1bar when cold, but when the system is hot and running the pressure doesn't rise much, is this a problem??

everything seems to be working ok, ie hot water tank is hot , all the rads heat up ok.

my thoughts is the expansion vessel is too big (18L) as I didn't really calculate it, I just erred on the big side.

is the lack of pressure a problem or would the system function much better with a higher pressure?

any thoughts welcome,

thanks carl

Doubtless this is the copper pipes used in this part of the house expanding as the hot water heats them up. So what is the best fix for this ?

I think maybe there is some kind of plumbers felt which can be slid under the pipes where they contact the joists to take away the friction ?

Any advice appreciated 

If you look at my brick thread I am currently having a house insurance claim.

The last stumbling block is them replacing the radiator that was damaged. The insurers contracting company is making a huge song and dance that the radiator in the lounge is unusual and requires special ordering in?

Its just a bog standard radiator to me?

When looking around it takes a day or so for one to come in but they are readily available. Although they are not sitting on shelves ready to be bought like some common radiators. 

Very quickly, I've realised I needed to balance the radiators. I've done a couple of rounds of balancing. First round, I dealt with the radiators that were heating first and obviously stealing flow from the other 4 (which are located in my higher heat loss rooms that I've not been actively heating).

At this stage, I'd left the 4 wide open (in hindsight not ideal). This made a difference in the speed of getting to temperature (2-3 hours, not 10) but the overall dT was still about 6C which is not great. Chart below from roughly steady state once to temp (I know the temps are fairly high, that's another thread that I will write at some point*).

Today I did another round of balancing, I've now restricted the flow on all the radiators now and have managed to widen the dT to nearer 9C and had planned to go back tomorrow and tweak some more.

I have some concerns though. Firstly, the locksheilds on most rads are now barely open and I'm concerned about minimum flows and noise in the pipework (noise so far is minimal but I'm clearly very close to more noticable noise). Is this what I should be doing or have I misunderstood something?

Secondly, since I've done this I noticed the boiler is now really short cycling (the cycling before at steady state was not great but now it's clearly problematic). My thesis is that before when the boiler cycled the initial burst of heat from the ignition got absorbed by the high flowing water fairly easily, with the more restricted flow caused by additional balancing work this burst of heat during ignition is not being lost in the flow and is causing the temp limit to trip and the boiler to lockout. During the lockout the return temp drops further giving more space for the heat from the next ignition. In theory you could deal with this via the controller but Wiser doesn't appear to have an easy way to do this (there is a hystersis setting in the debug output but no obvious way to change this).

Is my thinking right? Is there a way to address this with balancing / doing something different on the physical side?

* My system as installed (when the flats were built) is a mess. The radiators in my high heat loss areas appear undersized even when dealing with traditional dT of 50 and obviously totally inadequate for any sort of low temp heating. In the first screenshot here, the state seems steady but in reality the room was slowly losing heat as the OAT dropped and the heat input was capped but the minimum boiler modulation + max flow temp as I had it set. The second graph has a much higher max flow temp, but you can still see the minimum modulation is an issue (even though the property could likely absorb that heat ok).

I’m looking for some advice regarding my Worcester boiler which is currently showing fault code 227, which I understand is related to ignition failure.

I believe I may have found the cause. The condensate pipe from the boiler is connected directly to an external drain pipe, which seems to be blocked. We had heavy rain today, and I noticed that rainwater has likely backflowed into the condensate line, causing moisture or water ingress inside the boiler.

There are some signs of dripping water and dampness inside the bottom of the boiler, although not very severe but i can see water drips in every 10 seconds or so (pictures attached).

The same problem happened last year, and at that time it was much serious; the boiler fan was damaged and had to be replaced by an engineer. I watched the engineer to solve the problem. He replaced the fan and then only tried to dry the ignition components, then it worked. 

This time, I don't think the fan is damaged. I have turned off the power to let it dry out naturally but not sure if that will work.

Do you think it might start working again after leaving it to dry for 12–24 hours, or is it likely that I will still need an engineer to inspect it (e.g. ignition electrode, fan, PCB, condensate trap)?

Any suggestions would be really appreciated. Baby in the house so I prefer to solve the problem ASAP. Thanks!

Last year, after much effort to balance all rads unsuccessfully I eventally shut off the 4 (conveniently in one room) rads and shut the door on them!

Now I want to try and bring the 4 back to life. They are all the gtound floor and furthest from the boiler, all column rads with 2 being cast iron.

The remaining 15 are all hot and functioning well. 

Is it simply a case of turning the 4 back on TRV AND LS  and with abit of noodling hope they heat up or do I have to balance the whole system from scratch?

Have opened the bleed point and no air, so it isn't full of air.

There are two shut off valves in the cupboard underneath but both are turned on.

The rad has a 90Deg hand adjustable chrome twist valve on one end which I have opened fully. (see pic). I cannot see how to further access the internals of this valve e.g. to check for a stuck pin. There is no grub screw, and no ovious way to remove the twist cap ?

The rad has a 90Deg fixed valve on the other end with a screw off cap, but after removing the cap it doesn't have a lockshoeld type piece to turn, so how do I open it please ?

See Photos, and mucho thanks for any help.

Newbie to the site and looking for a bit of help/ guidance. 
Im currently refurbing my en suite, which involves the relocation of a radiator. 
I’ve drained the system (gravity fed) & relocated the pipes. 
Refilled the system, all rads working except downstairs lounge (most prob furthest from cylinder)

Ive tried all the usual stuff, bleeding, balancing but no joy. Lockshield & TRV all ok. 
Points to note-

There is no rad currently connected to the relocated pipes in the en suite & the un functioning rad (perhaps coincidentally ?) is the point where I drained the system from. 
Any ideas?!

With thanks 

Setup: 8kW GSHP → 2 UFH zones one side, 2 big rads in the middle, and no heating in the kitchen (all open loop). Pipework is 28mm from the HP, splitting into:

• 22mm for UFH (2 rooms), dropping to 16mm with 250mm spacing

• 22mm for downstairs rads (probably drops to 15mm underground)

• 15mm for all of upstairs (first metre is 15mm plastic, so more like 12mm).

Result: the last rads upstairs don’t really warm up, not helped by the HP’s 15-min cycles. It also means one side of the house (with UFH) gets really warm, while the rest is kind of relying on it. Planning to upgrade most of the upstairs pipework (luckily the routes are straightforward).

Debating whether to go 28mm copper with 15mm tees to rads. Heat-engineer calcs say 22mm is fine, but I may add UFH in the bathrooms later and it’d be handy to keep the option of running CH to the kitchen (downstairs is a concrete slab).

So… is 28mm overkill, or am I missing something obvious?

Side note (maybe for another post): I also need to tackle compressor vibration noise through the pipes. We only moved in last year, and the HP was installed back in 2008, so I appreciate it’s not the quietest. Anyone got experience with this? I’ve seen suggestions of using 900mm flexible pipes in a U, but not sure how practical that is.

This basically allowed me to fit a rad to each finished room, as they got done, without me having to drain the system when doing the next room. Now all worked fine, and still does Eight years later. The heat from each of the rads is controlled by a thermostatic valve at the inlet of each rad, and the lockshield valves are all fully open.

Now i have never balanced either the rads or the home made manifolds. the lengths of the pipe runs from the manifolds vary, from say 1.5 meters, to maximum 6 meters.

Due to the pipe runs, i expect the rads on short pipe runs, heat up quicker than the rads on longer runs. Would it be in anybodies opinion, worth balancing either the rads or the manifolds, to balance out the system ? I did size all the rads for each of the rooms, but do have One, (the smallest room) that seems to be a bit cooler than the other rooms.

in currently in end stages of my self build - at first fix stage. I need to spec rads on 1st and 2nd floor which provide wattage to match target temperature of each floor of 21deg. Ground floor we have UFH. My plumber has suggested speccing rads to work at 36deg flow. These rads are huge in places. A few options I have in brining down the rad sizes is to operate at a higher temperature (40deg or even 45) which im reluctant to due to reducing efficiency. Or I can bring down the target temperature however I don’t want to compromise on comfort. However as the house will be super insulated and is 3 storey high, would lowering the temperature by 1 degree as you go up be sensible? I.e 21deg ground floor, 20deg first and 19deg 2nd floor?