Pressure relief valve off CH pipe

[Dan Robinson]

http://shop.bsigroup.com

 

[JohnHarrison]

ATAG use a combined PRV/Condensate arrangement utilising a tundish and 11/4waste directly to the boiler.

ATAG combine the PRV and condensate into one discharge pipe? A plastic pipe into a plastic trap? I know there is high temperature plastic pipe. Does this discharge, which will be boiling water and steam, have to be high temp plastic pipe?

Onetap mentioned a condensate vessel/pump that takes the condensate and PRV discharge. The location we have is that a non-condensing Vokera SE with remote PRV means no discharge or condensate pipe from the boiler position to a drain, which will be about 30 foot or more of pipe under a floor. The SE is easier to fit.

The ATAG having a combined condensate/PRV connection will mean no secondary PRV but a condensate pump (the high temp one Onetap mentioned? Which model is it?) and will need a plastic pipe back to a drain over 30 foot away.

The Intergas will need a remote PRV and condensate pump, or a high temp condensate pump as Onetap mentioned and 15mm or 22mm plastic pipe back to a drain.

Reservations are the temperature 15mm or 22mm plastic can take from high temp condensate pump to drain.

intergas added a prv as an afterthought for the UK, this is positioned on the flow pipe after the valve by a standard 22-1/2 tee arrangement.

Lee, what valve is this?

Lee, a good point about heating boilers being converted to sealed systems. The sealed system kits, AFIK, have a 3 bar PRV and can be located anywhere on the system, not specifically the boiler.

1) The easiest to fit is the Vokera SE with a secondary PRV
2) The ATAG (and can be the same for the Intergas) will need a high temp condensate pump and over 30 foot of plastic pipe back to a drain with no secondary PRV.
3) Next is the Intergas with i) a secondary PRV and ii) a condensate pump with over 30 foot of plastic pipe back to a drain.

 

[Biggles..]

Why are you so determined to fit an SE boiler. DONT waste of money.

Lots of options such as pump house little giant etc for pumps.

Now someone mentioned steam in a PRV, don't confuse the intended purpose of a PRV with that of a TPRV. If you've got steam (100deg water) it doesn't mean the PRV will operate, it has no temp sense at all. It will only open at pressure.

Starting to loose the will, how about just employ a competent heating engineer and let him worry as this is all sounding very DIY.

 

[JohnHarrison]

Why are you so determined to fit an SE boiler. DONT waste of money.

Lots of options such as pump house little giant etc for pumps.

Now someone mentioned steam in a PRV, don't confuse the intended purpose of a PRV with that of a TPRV. If you've got steam (100deg water) it doesn't mean the PRV will operate, it has no temp sense at all. It will only open at pressure.

Starting to loose the will, how about just employ a competent heating engineer and let him worry as this is all sounding very DIY.

Lee, it is not DIY at all. I have laid it all out quite simply and professionally. The choice of combi is not mine. The idea is to use waste space in a chimney breast with me doing the groundwork. Lee, steam could come out of a PRV for sure. It may be a remote chance but it can. Just one time steam being very hot water run in a plastic pipe not suited for such temps, under a floor, and then a rip up of the floor and a re-think. So we want to get it all sorted beforehand.

Why I am in the frame is every time he got a guy around all said you could not fit the combi in the chimney breast, spouting about PVR and condensate problems, which is total garbage. The flat is exempt from condensing boilers and it can be very simple for a non-condensing combi in the breast. These so-called professionals did not know the laws to condensing boiler exemption and relating to secondary PRV (some here did not) and condensation pumps, etc. They want a quick easy buck doing a straight combi exchange on the outside wall. This kitchen is being fitted out to top specs and quality and a combi and its pipes in the middle of it is not wanted or needed when unused space is beckoning.

I do not see how a Vokera SE is a waste of money. I actually have one. I am very happy with it and it is a very simple combi indeed. The fact is the running costs are not much more than condensing combis. But the final choice is not mine, as it is not my money. If it was me I would go for the Intergas with a secondary PRV and a condensate pump.

As an aside, do these condensate pumps have a switch that cuts out the boiler if the pump fails, like the one inside the Bermuda? If there is a risk of a flood then these need careful consideration.

 

[JohnHarrison]

I found that Polyplumb plastic pipe is rated for maximum 105C service temperature and 114C fro malfunction temperatures. That should be OK for the condensate pipe from the condensate pump to the trap at the drain.

 

[Biggles..]

No requirement to use high temp plastic, that's only mentioned in G3/NHBC docs for TPRV's.
ATAG don't specify it in their instructions either.

As for your SE and chimney breast, why aren't you looking at a condensing combi, set as b23 utilising a one piece flue liner system or a boiler that will allow the use of an ubbink kit????

Vokera SE have one use,SE ducts-other than that don't bother.

 

[JohnHarrison]

No requirement to use high temp plastic, that's only mentioned in G3/NHBC docs for TPRV's.
ATAG don't specify it in their instructions either.

Lee, does than mean any boiler's PRV can empty into a plastic drain trap as long as it has a tundish? If that is what ATAG are doing well I would assume it is applicable to all combis.

As for your SE and chimney breast, why aren't you looking at a condensing combi, set as b23 utilising a one piece flue liner system or a boiler that will allow the use of an ubbink kit????

Vokera SE have one use,SE ducts-other than that don't bother.

Lee, I have an SE and it is a superb combi. I mentioned that three combis are in contention in the last few posts of mine. Two are condensing combis. The problem with a condensing pump, is that is it is another thing to go wrong and reduces reliability. I thought occurred to me earlier. A condensing tumble dryer can be fitted at the far end of the kitchen and use the condensing pump to empty into. This gives great flexibility in kitchen design. This is another plus point for a condenser over the non-condensing Vokera SE.

I found out what b23 is and Googled ubbink. I will look at the combi makers flues first before going to a third party. ubbink do a one piece flexible flue. That means the hot gasses up the flue liner and the air can come down the brick chimney not needing a pipe to the outside up the chimney for the air intake. A short pipe with a cap on it, to stop debris entering, from the boiler can poke into the chimney flue and be the air intake. If that is possible, well nice.