help with identifying part

Just moved house which has an ideal istor boiler. We had the same boiler in out last home and have a british gas homecare agreement as we knew it would be problematic.

We have found that when the hot water was being heated the radiators were hot and that after the hot water had been heated that when initially running the cold water tap the flow would contain very hot water.

British gas agreed with my verdict that the diverter valve needed replacing to fix the radiator issue and they suggested that the thermostatic valve was the likely culprit for the hot water issue.

Both parts have been replaced and the radiators are no longer hot

But still getting hot water when initially running the cold water tap

can you help me understand the name of the part in the attached image as I think it might be the cause or if you have any suggestions, I would really value them.


Thanks

James

I THINK that its just a hollow manifold!

But would like to see what is below it and where the 22 mm pipe to the left goes to.

I am guessing that the cold in is the pipe coming up and the 22 mm pipe to the left is the cold water out.

If that's the case then its probably just a slug of cold water which has been heated by conduction from the blending valve.

Looking at the installation manual might give you some clues.

These unit are usually a prompt for an engineer to become busy or to go on leave!

Tony

Hi

Sorry for long delay since your reply. Just back from holiday.

British Gas replaced the manifold which has a non return valve at the bottom of it where the cold comes in and also the mixer was replaced. After doing this we still get hot water coming through the cold.

So then Ideal visited and suggested that the cold out is designed for cold to a shower only and that a non return valve should be fitted in the hot out.

Instead they have adjusted the cold out so that it is branched from the cold in and below the non return valve in the manifold.

But still the problem exists. I need to double check but Im sure when my wife ran the downstairs cold tap, my finger felt very hot water by touching the cold out.

Im perplexed and would like to get to the bottom of the problem, and especially as there are about 30+ houses on the estate that are likely to have the same problem.

Im going to post a new thread in the forum as originally I was trying to identify the manifold.

Thanks for your replay and I welcome your further thoughts.

Only other way hot could come into the cold would be a passing blending valve like on a shower.

original problem prob due to the hot water expansion vessel forcing hot water down the cold due to incorrect piping, (which has now been sorted looking at your second photo), this could still be happening if the non return valve in the manifold is faulty, try feeling the cold inlet then get someone to open a cold tap and see if the hot is backing up
otherwise it could be a problem elsewhere as per Toms' post

Matt

matt1e said:

original problem prob due to the hot water expansion vessel forcing hot water down the cold due to incorrect piping, (which has now been sorted looking at your second photo), this could still be happening if the non return valve in the manifold is faulty, try feeling the cold inlet then get someone to open a cold tap and see if the hot is backing up
otherwise it could be a problem elsewhere as per Toms' post

Matt

Click to expand...

Hi Matt

Thanks for your post. The manifold was replaced prior to change in piping and the engineer said it contained a NRV. Is a NRV small?

I tested holding the cold in, and my wife turned cold tap on in the kitchen and the cold in when mega hot - unbearable. Would this indicate a duff NRV?

I have an engineer looking at the expansion vessel next Monday.

askjim said:

Hi Matt

Thanks for your post. The manifold was replaced prior to change in piping and the engineer said it contained a NRV. Is a NRV small?

I tested holding the cold in, and my wife turned cold tap on in the kitchen and the cold in when mega hot - unbearable. Would this indicate a duff NRV?

Click to expand...

no probs Jim, to answer your questions

1)How long is a piece of string?
if your question is could that manifold incorporate one then yes

2) yes, if you have access then try it again and see if the hotwater tracks back right along the cold inlet

I have an engineer looking at the expansion vessel next Monday.

Click to expand...

There's nothing wrong with it. get him to check the precharge if you like but I'd say its doing its job
if the NRV has failed either get the manifold changed under warranty or fit an external check valve (between the cold water branch off and the inlet to the unit)