zoothorn

My (rotten) ASHP. Update.

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ASHP in this instance has all the wet connections in the house so I can’t see how it’s losing pressure without it being visible. Only place I would do a bog roll test is the over pressure valves and put a sheet of clean dry loo roll over the end of the discharge into the tun dish to see if there is an over pressure leak 

 

Did they fit a new hot water tank too ..?

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Could it just be that every time you have something done to try to fix the system (eg change the pump), that air has got in again?

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@ProDave if there are no water leaks, there is no leak in the pipework. A leak is easy to spot. I don't find any water leaks.

 

So, if the system is losing pressure, & there are no leaks, & I have to keep jigging the taps to increace pressure, then -something- is wrong with it.

 

The only other thing that can be leaking is air. I was told by installers that after a new pump is installed, then it might well be the cause of this pressure drop after 2 weeks. If this is the case, & Vaillant installed the new pump, bc of a faulty one, then you cannot expect the installers to come back to rectify anything ascociated with this new install. It just doesn't figure.

 

I also notice an excess of water coming out of the outlet pipe outside, from the cylinder, only after this new pump is installed. Now if this isn't correct/ if this is a minor fault too/ then again: I can link this water spill to the pump install, & Vaillant changed the pump due to their poor hardware, therfore I just wouldn't expect the installers to have to come out & fix this too if they didn't install it.

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1 minute ago, Roundtuit said:

Could it just be that every time you have something done to try to fix the system (eg change the pump), that air has got in again?

 

This was put forward as a strong possibility, by the installers (who just told me immediately after install that if anything wrong, call them 1st before Vaillant). But this time I'd think calling Vaillant is correct, as they replaced the pump last week.

 

As it costs alot to call (& wait) Vaillant, I emailed installers/ who called back asap & told me how to rejig pressure again: mentioned it was likely linked to the new pump install too, just like you suggest Roundtuit.

 

So surely, its -Vaillant- to come back out (if needed to/ if it recurrs), not installers. And so, they'd be coming out to fix a fault of their system, not of any incorrect work the installers did.

 

 

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7 minutes ago, zoothorn said:

I also notice an excess of water coming out of the outlet pipe outside, from the cylinder,


there is your problem (I think) the only outlet pipe is a release pipe to stop excess pressure in the system, sounds like you’re pressure release  valve is leaking (I had one of these in the past.) ( but a proper plumber will be along in a mo 🤷‍♂️).

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Just now, joe90 said:


there is your problem (I think) the only outlet pipe is a release pipe to stop excess pressure in the system, sounds like you’re pressure release  valve is leaking (I had one of these in the past.) ( but a proper plumber will be along in a mo 🤷‍♂️).

 

Aha! yes of course, if you mean here is the mystery "leak"? Right that makes sense. Its definitely linked to the new pump: I have only seen this excessive water (I assume it is a bit excessive, & not normal) after the new pump fitted.

 

So is it a problem of the innitial installers? surely you can't put this problem in their intray to sort out.

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You might be on to something if you are seeing water leaking from an outside vent pipe.  This could be your hot water from the hot water tank, but it could equally well be the water that is going missing from the heating circuit.  They are two completely separate things.

 

Taking the heating system first, this is a sealed system that is charged to a set pressure then the water is turned off.  There is an expansion vessel that will absorb normal rise and fall of pressure as the water heats up and cools down.  As a safety feature this has a pressure and temperature relief valve that will let water out if the pressure gets too high.  This is the one that will cause the low pressure error if it loses water for some reason as it does not automatically get topped up.

 

Now the hot water cylinder.  That is constantly topped up with cold mains water in, via a pressure relief valve to limit it to a safe pressure.  That too has an expansion vessel (a larger one) to absorb changes in volume as the water heats up.  This will have over temperature and over pressure relief valves that will discharge water if it gets too hot or the pressure gets too high.

 

You need to follow the dripping discharge pipe into the house and find where it goes and which one is discharging.

 

Both will discharge via a tundish that looks like this

 

3890V_P&$prodImageMedium$

The open bit in the middle is so you can see if it is discharging water.  It might not be discharging all the time, so this is where you want to insert a bit of tissue paper into both of them, and check regularly to see if the paper is getting wet.

 

If you find one of the tundishes is discharging water, get your installers back and show them which one and get them to check it and fix the problem.

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15 minutes ago, ProDave said:

You might be on to something


I said a proper plumber, not an electrician 🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣

 

i,ll get me coat.

Edited by joe90
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@ProDave ok this is gaining clarity now. Yes Ive seen this black thing, I easily traced the outside outlet pipe back to this thing inside the house..  & since this pump installed notice it drip driping away sometimes even a slight stream.

 

I was told by installers, to expect a bit of water asap after the new system installed 3 months ago. That it did, then settled down after a few days (never ammount I saw a few days ago, a week+ after this new pump fitted tho).

 

I still feel reluctant to ask the installers back, if/ as seems highly probable, its an 'after-issue' directly linked to a new pump a Vaillant engineer's just fitted.

 

But you still think its for the installers to rectify-?

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Where does the pipework go after the tundish? (Black thing), any chance of a pic.?

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3 minutes ago, joe90 said:

Where does the pipework go after the tundish? (Black thing), any chance of a pic.?

 

Straight out the wall joe to the outlet pipe, slight downhill etc.

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Noooo, the other way, what’s it connected to? Which bit of plumbing is producing this water?

Edited by joe90

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A tundish should NOT normally drip.  It is there as a warning so you can see if it is dripping in which case you know something is wrong.  So if it is dripping then something IS wrong and it is up to the installers to come and fix it.

 

Don't let them fob you off with any notion that it is normal for it to drip.

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3 minutes ago, ProDave said:

A tundish should NOT normally drip.  It is there as a warning so you can see if it is dripping in which case you know something is wrong.  So if it is dripping then something IS wrong and it is up to the installers to come and fix it.

 

Don't let them fob you off with any notion that it is normal for it to drip.

 

ProDave- ok that's conclusive as to a problem then thanks. But I'm back to same thing: this only started after new pump Vaillant fitted.

 

Are you referring here to Vaillant as effectively being the installers on this issue then?

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Whoever you paid money to to install it. Did you pay  Vailant to supply and install it, or did you pay your builder or a plumber to install it?

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Just for my piece of mind where is it coming from,???. Follow the pipe above the tundish and let us know, or take a pic to show us.

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1 hour ago, PeterW said:

ASHP in this instance has all the wet connections in the house so I can’t see how it’s losing pressure without it being visible. Only place I would do a bog roll test is the over pressure valves and put a sheet of clean dry loo roll over the end of the discharge into the tun dish to see if there is an over pressure leak 

 

Did they fit a new hot water tank too ..?


Hi Peter sorry missed this reply.. the innitial install included a hw cylinder yes. Pic for joe Of it coming up..

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2 minutes ago, joe90 said:

Just for my piece of mind where is it coming from,???. Follow the pipe above the tundish and let us know, or take a pic to show us.

 

FBCD1235-BE08-46C4-81C4-1101ECA2138D.jpeg

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^^ If that is the tundish that is dripping then you have TWO faults.

 

That is the tundish for the hot water, and it means either the over pressure valve (with the blue knob) or the over temperature valve (with the red knob) is letting water out.

 

So that is a fault that needs fixing, potentially it is unsafe at the moment with an unknown fault.

 

BUT that will not be the cause of the heat pump tripping on low pressure.  There will be aoother set of valves and another tundish somewhere, quite likely near the inside half of the ASHP.  You have a second fault causing the heating circuit to lose water.

 

I don't presently have much confidence in your installers.......

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9 minutes ago, ProDave said:

Whoever you paid money to to install it. Did you pay  Vailant to supply and install it, or did you pay your builder or a plumber to install it?

 

Didn't pay either!

 

You think the installers should rectify a problem linked to Vaillant fitting the new pump-?

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@ProDave beat me to it.....just exactly who installed what?

 

43 minutes ago, zoothorn said:

Didn't pay either!


then don’t pay the bill till this is sorted out!

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Wasn't it done on some grant scheme, so we all have paid for it, already.

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Well SOMEBODY installed it. That SOMEBODY needs to come back and fix it.  We can't help you determine who that was.  A clue might be who signed the commissioning paperwork for the unvented cylinder?

 

But it is hardly the fault of Vailant that the blow off valves are passing water. They didn't make or fit those did they?

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32 minutes ago, zoothorn said:

You think the installers should rectify a problem linked to Vaillant fitting the new pump-?

 

Its not clear if they are definitely linked..

 

In my limited experience I have found that Pressure Relief Valves (PRV) are fragile temperamental things. If the pressure goes up too high just once (so that a little water comes out) then they can start leaking all the time. Not quite sure why but I've had at least three or four do that. So if you get the PRV replaced and need to pressurise the system yourself in future be careful not to go so high that the PRV opens. 

 

As you know water expands and contracts when it heats up and cools down. Others have already mentioned that there should be a correctly sized expansion vessel (or two) somewhere that accommodates the expansion of the water so that the pressure doesn't rise too much and the PRV doesn't open. If the expansion vessel is too small (a design fault) or has lost its charge (needs pumping up or replacing) then the pressure can rise too much causing the PRV to open and in my experience its quite likely to fail with a constant slow leak. 

 

None of this is specific to ASHP. I've had this issue on both gas and oil fired systems. 

 

If you can find the expansion vessel(s) they may have the size writtin on them and if you know how big the tank is it might be possible for one of us to check if the expansion vessel is too small. 

 

 

 

 

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31 minutes ago, ProDave said:

Well SOMEBODY installed it. That SOMEBODY needs to come back and fix it.  We can't help you determine who that was.  A clue might be who signed the commissioning paperwork for the unvented cylinder?

 

But it is hardly the fault of Vailant that the blow off valves are passing water. They didn't make or fit those did they?

 

Understood. So if my low pressure issue, & this new issue I didn't even know was an issue until you said so, is connected with the installation of anything -other- than the new pump, I fully take your point that the installers should be those who come back & fix it.

 

But ProDave how can this dribbling -not- be connected to the new pump install, if, it only happened as soon as it was fitted & not before tho? pure coincidence?

 

 

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