New system, HW on only but rads getting hot!

[JDLDIY]

Just had a completely new system fitted, comprising Worcester Bosch Greenstar 28HE condensing system boiler, new cylinder, pipework and rads. The system is controlled by a separate controller and 2 honeywell motorised valves.

We've got to the stage of pulling our hair out though, as the rads are getting warm if not hot when the HW is on only. The installer has subsequently fitted a bypass with a gate valve between the primary flow and return and extended the HW return so that it connects to the primary return much closer to the boiler, but still it is heating the rads up. He also replaced a motorised valve which he thought might be faulty.

If there's anyone who feels they may be able to shed some light on this I can post more information, diagrams and photos. I'm desparate as I need to get on with rest of the kitchen!

Cheers
JD

 

[breezer]

obviously there is something wrong / not right, call the installer back, but be nice.

How would you like it if you go to site to do your job, and person you are working for starts to tell you how to do job, not nice is it? call him back, and expalin there is still a problem

 

[djbunny]

he should only be fitting an auto bypass valve not a gate valve, building regs, but thats not the problem it may be he has not connected all the heating returns up before joining to the primary return causing a reverse circulation through the heating. You need to find where the heat is coming from by switching system on when cold and seeing where the rads get hot from check to see if return on the rads get warm before flow.

 

[JDLDIY]

Problem is it's difficult to give the whole story without making an extremely long post. The installer and the guy from WB are both at wits end and I have suggested that I may as well see if an expert on here (and posting on plumbingpages.com) has any light to throw on the matter. So they are hoping to get some feedback from this, maybe someone else has fitted this boiler and had this problem.
I'm playing around with it tonight, seeing if I can ascertain where the heat is coming from (flow or return etc), can anyone tell me how the bypass works and how it should be set up?

 

[Gas2Air]

It can only be a couple of things. CH valve passing or open in manual position, reverse circulation, return from cylinder piped wrong, it should be piped as the last return to the boiler return.

A bypass would have no effect, its purley a bypass.

It's fairly easy fault to deduce as long as you got a pro in?

 

[Gas2Air]

Check the wiring, i've found the same fault led to heating on and hot water on reversed behind the programmer.

 

[JDLDIY]

Thanks Gas2Air, what you are saying makes sense to me.

It can only be a couple of things. CH valve passing or open in manual position, reverse circulation, return from cylinder piped wrong, it should be piped as the last return to the boiler return

The CH valve has been replaced now so that should be OK. How would I test for reverse circulation? The cylinder return goes through the floor, down the wall parallel to the boiler and then T's into the primary return, the closest return to the boiler though is the CH return T.

Check the wiring, i've found the same fault led to heating on and hot water on reversed behind the programmer

the heating hasn't come on though by accident, I mean the heating flow valve not open/activated.

Blast need to find out how to make that image bigger, will edit shortly.....
Hmm...I take it that understandably there is a size limit to photos then?

Right then, starting from left to right;
1 CH up and down flow
2 HW
3 Flow connection to boiler and bypass to return
4 Cold water feed (connected to primary return)
5 Gas connection
6 Primary return
7 15mm HW return T'd into primary return
8 Overflow/vent

How does this look to you all?
JD

 

[Gas2Air]

Try putting the heating on, no hot water. Feel any nearest rad flow pipe it should be on the wheelhead end or trv end. Now turn off heating and put on hot water, feel the rad flow again, if its cold and the return pipe from rad is hot, you got reversed circs.

It may be that the upstairs rad return pipe tees in somewhere under the floorboards into the cylinder return and the cylinder return THEN tees into the boiler return. Assuming you have a two pipe system anyway!

 

[JDLDIY]

It may be that the upstairs rad return pipe tees in somewhere under the floorboards into the cylinder return and the cylinder return THEN tees into the boiler return. Assuming you have a two pipe system anyway!

Na, the radiator return comes straight back into the boiler and the cylinder return is the smaller pipe next to it - pipes 6 and 7. I've gone and put CH return for 7 but it's the HW return in 15mm pipe - Doh!

 

[JDLDIY]

Any suggestions as to why the image just got dropped? The link anyway is http://us.f2.yahoofs.com/users/40683f59_8f24/bc/f750/__sr_/ebc0.jpg?phSptDBBVwl36Drr

 

[ChrisR]

IE can't see this pic OR the one on PP!

 

[big-all]

sorry unnown host here as well

 

[JDLDIY]

ChrisR - thanks for replying, can you view the picture when you click on the link above? Checked my picture hosting settings and no reason why they aren't in the public domain. They come up OK on my computer including in the original post above now.
JD

 

[JDLDIY]

This is obviously a problem my end but I can't see why, will amend tomorrow....
JD

 

[ChrisR]

Still no. Haven't set 128bit security have you?