Ground Source Heat Pumps

beardymarrow

Hiya,
Red one, I would guess is the expansion tank for the central heating and white one is the expansion tank for the domestic hot water. The valve on the DHW one is a pressure relief valve so it'll release water to lower the pressure if it gets too high (shouldn't happen in normal operation).

1. No, a GSHP is not "pressurised" as such. Your plumber is showing his ignorance. Yes, there is some pressure in the central heating, but only 1-1.5 bar when cold, same as if you had a normal gas boiler.

2. The expansion tank is not part of the GSHP as such, so any plumber who had seen a hot water tank before, could replace it. I replaced mine myself as the diaphragm had perished and it was cheaper and a hell of a lot easier to replace than repair, and I'm not a plumber by any means.

JHen

Thanks for the prompt reply - as always.
So could a perished diaphragm cause the banging noise I am hearing ?

beardymarrow

JHen wrote: »

Thanks for the prompt reply - as always.
So could a perished diaphragm cause the banging noise I am hearing ?

Hi, it's possible, but I'd have thought it would happen when using the hot tap, not the cold, which might mean it's a cold water feed expansion vessel. It may just need re-pressurising (there's a car tyre type valve on the top). If it is on the cold feed I think it needs to be set according to the pressure expected by the dhw tank, but I'm out of my depth on that to be honest. Either way any plumber who can work on a system that has a dhw tank would be able to sort it out. A new tank would only be 40 quid or so, if it does need one.

lovesgshp

The red one should have no pressure, as just a expansion tank. Tap it to see if it is empty, as the diaphragm can fail. If it sounds hollow the ok.
The white tank. Is this on the line from the ground loops, as that should have little influence.
Have you checked the DHW tank for air, as this could be the problem.

lovesgshp

Will you just refresh my memory on the system, C series or E with water tank.

lovesgshp

Normal guidline pressures:
4 bar cold water input into system.
1.5 to heating system.
0.5 to 1.00 ground loop. ( it can be 1.00 and drop to 0.5 on operation)

JHen

Its an IVT HT Plus C7M. The white tank does have a tyre valve on the top (under a black cap). When I tap the red tank it sounds solid, where the white one does not.
"Have you checked the DHW tank for air". How do I do this? Is the tank part of the heatpump ?

lovesgshp

Take the front cover off the pump. Inside you will see the dhw tank. At the top of that there will be a small brass knurled bleed valve. Open it slowly to release any air and wait until you just get a water flow. Water could be hot!!!!
Red tank sounds as if it is full of water.

JHen

lovesgshp wrote: »

Take the front cover off the pump. Inside you will see the dhw tank. At the top of that there will be a small brass knurled bleed valve. Open it slowly to release any air and wait until you just get a water flow. Water could be hot!!!!
Red tank sounds as if it is full of water.

So I had the GSHP serviced on Friday and engineer checked the cold water vessel and said it was fine, he even removed and re-pressurised it but the banging is still there. Most cold taps/dw/mw cause the bang. It's not really loud but enough for me to hear when I'm in the room where the GSHP is or the room above. The engineer said it could be the cold water inlet valve but he was not able to replace he didn't have my old style one in his van. Again, I appreciate this is not a GSHP related issue.
PS The reports stated no air was found.

alastaid

Hi, i have an IVT GreenLine E11 installed in 2006 that has hummed away perfectly, however I now am getting HVT delta issues, and after reading this long thread the three way valve has gone, it wont activate even using the installer menu, just does nothing. It was installed with the MUT MR SPST CR M3 valve (also says ART 7.013.00570 on it), I think I have found a company locally to me that has the LK valve P/N 8733701136 (I hope this is the right one!) it looks like the electrical connector is the same for both valves, does anyone know if I can just replace with the LK valve and just plug the connector in without having to change anything? Thanks in advance.