ASHP low pressure help pls

[Beelbeebub]

1 hour ago, Dillsue said:

OK, but that's the shower that may need a pump, not a vented cylinder. We're open vented for CH and DHW and have a pump only on an indulgent en suite shower. Rest of house incl a second first floor shower isn't pumped.

You can do that too, or you can pump the whole hot water supply - either way you need a pump. On the plus side newer inverter pumps are pretty quiet and can provide nice even pressure without the old on/off/on/of pulsing behavior of the old ones.

[Beelbeebub]

20 minutes ago, sharpener said:

 

As installed mine had a compliant 22mm D2 setup taken into a first floor soil stack via a Hep2O bladderless trap.

 

Thinking this was where the restriction was I modified it so there was first a 2.5m drop to the ground floor and the trap went into the stack at that level instead.

 

But it is not much better and will still not take the full flow from the tprv. 

 

So I think that the whole concept that the pipe below the tundish needs to be only 22mm - one size up - is flawed, the regulations do not achieve their aim and are pointless. And a tundish hidden away in an airing cupboard slowly filling with water is NFG either.

 

Personally I think it would be better to have the relief valve piped in 15mm directly to waste with an electrical or mechanical alarm to indicate there is something wrong and possibly a small air admittance valve to vent the pipe but prevent smells. 

 

As a further twist the MCS surveillance visit on another house meant the HP installer was called back to move the tundish to somewhere slightly more visible (even though it was pre-existing and not part of his work). The D2 pipe is 28mm bc of the run length but has a 28mm tundish that will overflow too. So the modification is purely cosmetic, the tundish is still in an alcove off a loft above our bathroom, access is still via a ladder and a door which is kept shut so we will neither see or hear any overflow condition. Which is why I test the tprv whenever I am up there, at least I know it is not stuck and the valve seating is washed clean.

 

I think the issue is with air escaping. With a drop you essentially get air locks in the pipe. The water is trying to go down and the air is trying to go up. Paradoxically a bigger vertical might make it worse as there is more back pressure from the air lock before any horizontal section where the air can sit above the water. 

 

The idea of a tundish always confused me. 

 

 

I get there is a reason for them as an anti syphon device and there is a visual indication argument. 

 

Except the visual indication is useless if the thing is in a rarely visited cupboard and the antisyphon argument doesn't seem relevant if the pipe is leading directly outside or even if it's leading to a soil stack.

 

A clear glass section with a properly designed air admittance valve would probably be better albeit more expensive than a tundish. 

[canalsiderenovation]

Will fully update later but have a guy here now from same company whose first question was "who did the service?" Embarassing when I said same company you work for but different guy! This guy seems to know what he is doing been doing it 27 years. Expansion tanks just needed pumping up which he has done and DO NOT need replacing.... paid 50% deposit on the basis they said they needed replacing and guy is going to sort with office.

 

Is sorting that leak (pic I uploaded with the leak from the bottom of Gledhill tank) which he noticed right away. Will explain other stuff later on....

Edited 8 hours ago by canalsiderenovation

[ProDave]

Looks hopeful.  Can't wait for your later update.

[canalsiderenovation]

5 hours ago, ProDave said:

Looks hopeful.  Can't wait for your later update.

 

I spoke to soon. Now we have no heating or hot water and an error code. We had to leave the minute the engineer left as they were 2 hours late. He left the heating and hot water on. Clearly the error code came right after he left as our hot water is 18 degrees and the house is cold.

 

I am absolutely fuming. We are in an even worse position than before. I will be on the phone  to them at 9am in the morning!

 

[ProDave]

 

[canalsiderenovation]

Flow sensor is zero so that is the problem but I can't test any further. Within a few seconds of turning the heating on the error code comes up.

[-rick-]

Whats the pressure reading below the red tank?

[canalsiderenovation]

27 minutes ago, -rick- said:

Whats the pressure reading below the red tank?

Fine.

 

 

When I go to turn on the heating or hot water there is what sounds like a grind noise coming from below (I think the pump thing). 

 

I have sent a scathing email to the company. We are in an even worse position than 24 hours ago. How they have managed to cause more problems I have no idea. We had heating 24 hours ago and even hot water albeit with a leaking tundish. 

Edited 1 hour ago by canalsiderenovation

[-rick-]

4 minutes ago, canalsiderenovation said:

When I go to turn on the heating or hot water there is what sounds like a grind noise coming from below.

 

Looking at your earlier photos, looks like you have a couple of electronic valves down there. Normally make a whirring noise when operated (usually at start/end of a cycle).

 

Given the grinding noise I'm not confident to tell you to try again to try and identify the source of the noise (hopefully others can advise whether it's making things worse to try). But assuming the grinding is coming from a valve then either the engineer removed the head to work on / check the system and didn't refit properly (could be a quick fix) or the valve has failed (strange timing for that given everything else). They can be operated manually which might be enough to get you up an running but wait for someone else with more experience to confirm what to do.

 

My other thought is that if its the CH valve, then its entirely possible that this issue only affects the CH mode and the DHW mode will work. Again wait for others to speak up.

[canalsiderenovation]

Neither heating or DHW is working. I will be on the phone at 9am to the company asking that they either sort it or put everything back to it was when it was working 12 hours ago. 

 

When I attempt to turn either on there is a noise. I am not sure if it is coming from this or the tanks but this was not happening 12 hours ago.

Edited 30 minutes ago by canalsiderenovation

[Beelbeebub]

Have they left an isolation valve shut somewhere? Eg the ones usually by the HP outside? 

 

Pretty poor show though.