Question for those with an unvented ticket

[cr0ft]

Hi all. I have a new condensing system boiler which our gas fitter will be installing tomorrow. It's going to be installed right above a new unvented cylinder. As the airing cupboard they are both in is in the centre of the house, I want to run the PRV from the combi-boiler into the D2 pipework of the unvented cylinder (below the tundish). This way I will be able to tell whether or not the discharge is from the combi or the unvented cylinder in a fault situation.

Does anyone see any problem with this? I can't see any regulation that stops me connecting other relief valves to the D2 pipework.

 

[desrob]

Hi all. I have a new condensing system boiler which our gas fitter will be installing tomorrow. It's going to be installed right above a new unvented cylinder. As the airing cupboard they are both in is in the centre of the house, I want to run the PRV from the combi-boiler into the D2 pipework of the unvented cylinder (below the tundish). This way I will be able to tell whether or not the discharge is from the combi or the unvented cylinder in a fault situation.

Does anyone see any problem with this? I can't see any regulation that stops me connecting other relief valves to the D2 pipework.

your gsr plumber will advise you..for one moment reading between the lines, i thought you were going to fit it ,ha ha i know how stupid am i,.

 

[Mike Jackson]

The only issue I could really see would be overloading of D2 if both discharged at the same time and D2 was near the max length. Certainly better than teeing in above the tundish where there is a very minor risk of contamination of the potable water.

 

[desrob]

Hi all. I have a new condensing system boiler which our gas fitter will be installing tomorrow. It's going to be installed right above a new unvented cylinder. As the airing cupboard they are both in is in the centre of the house, I want to run the PRV from the combi-boiler into the D2 pipework of the unvented cylinder (below the tundish). This way I will be able to tell whether or not the discharge is from the combi or the unvented cylinder in a fault situation.

Does anyone see any problem with this? I can't see any regulation that stops me connecting other relief valves to the D2 pipework.

confusing thread, are you and if you are,why are you getting some one in,

 

[AWheating]

where does the discharge terminate?

 

[cr0ft]

Hi folks. Sorry for any confusion. I have my unvented ticket so I have fitted the cylinder but the gas fitter will be arriving tomorrow to fit the system boiler. I'm just not sure whether there's anything specifically preventing the PRV from the boiler being plumbed into the D2 outlet of the unvented cylinder. It discharges at low level outside the front of the house.

I'm not GSR, I subcontract out the boiler fitting on all the heating installs I do and I do all of the rest, controls and everything basically.

 

[cr0ft]

Sorry, my op was confusing. It should have read 'I am planning to ask the GSR to plumb the PRV from the combi-boiler into the D2 pipework from the unvented cylinder.' I just don't want to ask if it's illegal or anything like that, don't want to look stupid. My gut instinct tells me it will be fine tbh and I'm not aware of any regulations that prevent it being done.

 

[cr0ft]

D2 works out at a hydraulic resistance of about 8 metres so run in 22mm.

 

[GrahamM]

Nothing wrong in my opinion. Seen it done on number of occasions.
Run in metallic and has a safe, visible termination outside. Fits the bill!

 

[dancinplumba]

i have done this with electric boiler so i can tell which is passing, goes to an outside drain bout same length as yours an i am happy with it and tested it an it was fine :~

 

[cr0ft]

Cool, that saves having to run another discharge pipe the same way then. Thanks all!

 

[Howsie]

How will you tell if the PRV from the boiler is passing?

 

[cr0ft]

From the discharge outside and no visible discharge at the tundish on the hot water cylinder. That's why it's been plumbed in below the tundish.

 

[Howsie]

Why not fit two tundishes?

 

[cr0ft]

Could do I suppose, but there's no need is there? Or is there? Discharge from pipe + outside and no discharge from cylinder tundish = boiler PRV, discharge from pipe outside + discharge from cylinder tundish = TPRV passing?

 

[Howsie]

Ignore me. I'm losing my mind today.