6 bar safety valve discharging

[weeman]

Any help or advice would be very much appreciated on this one...

Been to a customer today who has a solar panel connected to her combi system and the 6 bar safety valve is discharging, its a tube type approx 10-15 years old, as far as i can see it has mains water running through it then back through a blending valve then through the boiler.

my question is what takes care of the expansion? or is it a case of just replacing the 6 bar prv?

The prv was replaced about 2 years ago by someone else but going by the how wet the flat roof is below (has small trees growing on it!) leads me to think this problem has been going on for a while and there maybe be other underlying faults.

Thanks in advance Jamie

 

[Pipes Plumbing]

Shouldn't be a solar panel on a combi boiler system... Where is the heat and expansion going to go?
Is this something that has been cooked up in a DIY style?

If there is no storage of the heated water by means of a cylinder or thermal store there will be zero benefit to the system.

I'm glad the PRV was discharging, otherwise the boiler or it's pipework could well have done an impression of a hand grenade...

 

[mountainman]

Sounds dodgy.
I've never come across a solar panel connected directly to a combi boiler nor one with mains water running through it.
Expansion should be taken up by a pressure vessel but a 6 bar PRV is way over the top.
You need a thorough investigation of the design, perhaps post some photos on this forum.

 

[weeman]

those were my thoughts exactly, i traced the pipe and it is definitely cold mains, i searched the whole house and loft and found no storage or expansion vessel.

it was apparrently sold and fitted by a solar company over 10 years ago but the customer could not find any literature on it.

the only thing i can think is that when the boiler was upgraded 3 or 4 years ago it was converted to a combi system and the panel should never of been hooked up BUT the boiler was installed by Worcester not some cowboy??

in the mean time i have bypassed the panel to make safe i will try and get back to get some photos to post.

 

[dancinplumba]

dodgy or what !!! love it worcester, down goes your reputation even more lolol

 

[Kev the gas]

Shouldn't be a solar panel on a combi boiler system... Where is the heat and expansion going to go?
Is this something that has been cooked up in a DIY style?

If there is no storage of the heated water by means of a cylinder or thermal store there will be zero benefit to the system.

I'm glad the PRV was discharging, otherwise the boiler or it's pipework could well have done an impression of a hand grenade...

Technically why ?

In practice it can be done and in safety terms can be and is done :-
The panel heats a cylinder in the loft.
The mains water to the combi passes through a second coil in the cylinder which preheats the water so the combi has less work to do.

I have seen this type of install many times, but I have always questioned the savings such a system can achieve.

Without seeing your installation I cant comment on whether it is installed correctly or not.

There are some very good Solar sales people around who unfortunately have tainted the industry selling systems that do work,
BUT cannot ever pay for themselves.

I would be very surprised if Worcester themselves fitted the boiler, maybe an accredited installer?

I install Solar systems and I have asked Worcester if they allow this type of preheat installation. They said it was unsuitable for condensing boilers.

Kev.

 

[mountainman]

OP says there is no form of hot water storage Kev.

Yes it would work with a twin coil thermal store but where is it?
MM

 

[dancinplumba]

the water for feed to combi comes from preheat cylinder itself not coil in cylinder, that's where solar fluid goes to heat the cylinder
imo

 

[gassafe]

dodgy or what !!! love it worcester, down goes your reputation even more lolol

Worcester Bosch don't install boilers...

 

[Nostrum]

Seen one similar like Dancin' said years ago, can barely remember the set up but i'm pretty sure the water in cylinder in loft was heated via coil (coil was heated by panels) down to a thermostatic 3 way valve, if hot enough water went straight to taps, if not, water went through boiler.

I can only think the reason Worcester said it was not suitable for a condensing boiler was because the TD wouldn't cause the boiler to condense? Either that or because some of their boilers don;t even have hot water temp control!?

 

[dancinplumba]

Worcester Bosch don't install boilers...

no, i know, just not a fan of wb, soz...but if its installed by a wb accred installer....lorgi lordi lol

 

[weeman]

sorry my mistake, it was installed by an accredited installer and been serviced by worcester since.

 

[dancinplumba]

lol, worcester know there stuff..yes indeedy