No return valve on combi

[CBF]

The previous post is dangerious

oh dear it's not my post that dangerious it's either the fact you are reading the post wrong or your knowledge isn't quite what it should be, the OP's boiler has a built in filling loop, the check valve her installer is talking about is on the cold main into the boiler & the only way you will get contamination of the supply is if the plate heat hex corroded through (& thats providing there isn't already a check valve built in to the boiler), highly unlikely, yes it should have a check valve on it but it's not a life or death situation & is something the installer could do at the annunal service, providing the filling key is removed all should be ok

 

[John506]

OP,

Sit down, have a cuppa, put your feet up, and stop worrying

 

[holty]

taxes wrote:
The previous post is dangerious


oh dear it's not my post that dangerious it's either the fact you are reading the post wrong or your knowledge isn't quite what it should be, the OP's boiler has a built in filling loop, the check valve her installer is talking about is on the cold main into the boiler & the only way you will get contamination of the supply is if the plate heat hex corroded through (& thats providing there isn't already a check valve built in to the boiler), highly unlikely, yes it should have a check valve on it but it's not a life or death situation & is something the installer could do at the annunal service, providing the filling key is removed all should be ok

sorry CFB you should be ashamed of yourself. its so very dangerous. its actually worse than the guy thats altered his balanced flue.

 

[ianmcd]

you have absolutely nothing to worry about just dont leave the white key in unless you are actually re-pressurising your heating system

 

[turnpike]

Thanks. Good advice and suggestions. It's just a bit of fact finding anyway so I might have a slightly better idea of what might be going on.

Personally I think based on the instruction manual and advice given by ianmcd, CBF and others, it sounds unlikely the water is being contaminated. The non return valve is probably for the cold main into the boiler. In which case I'd need an expansion vessel also.

Anyway this is just for my info and I'll get it checked on next service. Thanks again.

I don't think any of the posts are dangerous unless read and acted upon by someone who doesn't take sensible precautions and informed choices. They're just opinions from people who know more than me about plumbing.

 

[turnpike]

Hi,

Sounds like it, but why they call it "Integral" when it is not supplied with the boiler, beats me. Look at where you insert the key to top up and it is probably an isolation valve at the end of a flexible pipe. That valve may contain the non return element; if so it will be much longer than a simple isolation valve. If you can post a photograph of it, that would help.

Question. What are the circumstances in which the manual says "isolate and remove the filling loop cconnection....".

If you tell me the name and model of the boiler I may be able to look up the manual on the internet.

I am going out for the rest of the day now.

Sorry just noticed the questions in this comment.

I'll try to look at it tomorrow to see what the valve looks like. The section of the manual I quoted from were for initial filling.

 

[CBF]

taxes wrote:
The previous post is dangerious


oh dear it's not my post that dangerious it's either the fact you are reading the post wrong or your knowledge isn't quite what it should be, the OP's boiler has a built in filling loop, the check valve her installer is talking about is on the cold main into the boiler & the only way you will get contamination of the supply is if the plate heat hex corroded through (& thats providing there isn't already a check valve built in to the boiler), highly unlikely, yes it should have a check valve on it but it's not a life or death situation & is something the installer could do at the annunal service, providing the filling key is removed all should be ok

sorry CFB you should be ashamed of yourself. its so very dangerous. its actually worse than the guy thats altered his balanced flue.

get real, there are thousands upon thousands of combi's that don't have a check valve on the cold main into the boiler i'm not talking about the filling loop (which of course should have a check valve on it) & neither is the OP & i don't hear about millions of people dying of poisioning.

or were you being sarkie if so then you can have a

 

[taxes]

taxes your going way over the top. sounding like a student thats just passed all his reg courses.

Hi,

You could not be more wrong but I see no point in arguing with you.

The following is an extract from one water authority's byelaws:

"Topic B22 states -
“Heating system appliances of any size in purely domestic premises, and single appliances or combinations of appliances rated at an output of not more than 45kW (150,000 Btu/hr) in other types of premises (such as small offices), should be regarded as a fluid category three backflow risk. For such appliances, a temporary filling loop with a double check valve for backflow protection is permitted, the filling loop being disconnected when it is not in use. The double check valve must be installed before the filling loop and remain on supply pipe connection when the loop is disconnected. For appliances above this heating output, in other than a house, the filling system would require fluid category four protection.”

It is not for me, nor you, to say that the rules should be ignored. We HAVE to obey them.

The Worcester device is NOT a temporary fitting, is not disconnected when not in use and is not a check valve. It does not prevent backflow if the boiler pressure at the time of attempted filling is higher than the mains supply. Highly unlikely I know, but that is precisely what the water authorities are trying to guard against. This guy is worried about possible contamination of his drinking water and the simple fitting of a non return valve will remove all such possibility.

 

[taxes]

get real, there are thousands upon thousands of combi's that don't have a check valve on the cold main into the boiler i'm not talking about the filling loop (which of course should have a check valve on it) & neither is the OP & i don't hear about millions of people dying of poisioning.


I've just noticed this comment. Obviously you are missing the point. All the comments should be referring to the mains supply to the filling loop. No one, apart from you, is referring to the mains feed THROUGH the hot water supply which, of course is not required to have a check valve.

 

[Iddy]

The Worcester device is NOT a temporary fitting, is not disconnected when not in use and is not a check valve. It does not prevent backflow if the boiler pressure at the time of attempted filling is higher than the mains supply.

Actually the WB integral filling loop DOES contain a non-return valve, so IS a check valve and WILL prevent backflow . . .

 

[turnpike]

This guy is worried about possible contamination of his drinking water and the simple fitting of a non return valve will remove all such possibility.

I think I'm getting the general idea now. Please correct me if I'm seriously wrong.

The non return valve would go on the cold feed into the boiler. It is a safety precaution which is only actually needed while the loop for filling or topping up is open (which in my case is the plastic key that opens a valve).

I also think the combi install manual insists on an expansion vessel if the non return valve is used. Interestingly the manual does not seem to care if the non return is fitted, only that the vessel is in place if it is.

So based on how my boiler appears to be set up currently, I'd only be at risk during or immediately after having opened the loop to top up the heating?

Atleast this means I don't have to run the cold tap a while EVERY time I drink from it as I wasn't sure what the risk was.

 

[ianmcd]

Quote "I'd only be at risk during or immediately after having opened the loop to top up the heating?"

You wont be at risk at any time even when you are topping the pressure up, as Iddy correctly states the WB Charging link which some posters are calling the filling loop already incorporates a non-return valve inside the plastic section

 

[CBF]

I've just noticed this comment. Obviously you are missing the point. All the comments should be referring to the mains supply to the filling loop. No one, apart from you, is referring to the mains feed THROUGH the hot water supply which, of course is not required to have a check valve.

Quote from the OP "It's a Worcester Bosch greenstar junior 28i fitted nov 2008. I think the non return valve would be on the cold feed but I don't know. I heard something about protecting from contamination of the drinking water"

there is a clue there "cold feed" you are the one that started going on about the filling loop no one else did, plus if you knew about the OP's boiler you would know it has an in built filling loop & therefore is very unlikely to have a seperate one

 

[taxes]

Hi,

Although there is no mention of a check valve in the Worcester manuals, I have just confirmed with Worcester Technical Dept. that there IS a check valve incorporated in the right hand side of the Integral Charging Link. The technical guy did not know this offhand and had to get a charging link and inspect it!

So the short answer to the original question is; Your original installer was wrong. You do have a check valve in the place you need it.

BTW I have always found Worcester technical guys (& dolls) extremely helpful

 

[turnpike]

Well that was all very interesting and I definitely know more now than I did a couple of days ago Thanks everyone for your advice.

taxes: is that specifically for the version of the combi fitted nov 2008? or did he check the latest build?