vented central heating

Amikom · Posted: Sun Jun 17, 2007 8:41 am Post Subject: vented central heating

We recently had a leak in the ch system which brought the ceiling down !!! System drained and leak fixed but when trying to refill ch system no water coming to rads!! The expansion tank in roof is full though - assumption we have blockage in feed pipe! The question I have is do we just get someone to fix the blockage or, as suggested by them, change the system to an un-vented system? If so approx how much would that cost? BTW we have a megaflo hot water system if that makes any difference.
Any help would be most appreciated.

charlieboy3 · Posted: Sun Jun 17, 2007 9:13 am Post Subject: blocked cold feed

the chances are that the cold feed is blocked, the most likely place for this is where it enters into the system. You are most likely to see a 15mm pipe cold feed, and a 22mm pipe open vent join the system just before the pump. the blockage will be where the 15mm connects.

weareleeds · Posted: Sun Jun 17, 2007 10:49 am Post Subject:

You can't just seal any system first & foremost the boiler must have an o/heat stat but you may also need to change rad valves to meet 3 bar pressure

gas4you · Posted: Sun Jun 17, 2007 7:22 pm Post Subject:

Megaflo is nothing to do with the heating side. As previously stated cold feed blocked or you need a boiler with an overheat stat.

Removing cold feed blockage is a hell of a lot cheaper than converting to a pressurised system.

As you obviously have not filled the system yet, how do you know you have fixed the leak

__________________
Dave
DRL Gas Services

moliver34 · Posted: Sun Jun 17, 2007 8:24 pm Post Subject:

wait an see

corgiman · Posted: Sun Jun 17, 2007 8:27 pm Post Subject:

moliver34 wrote:

wait an see

Ahhh the water regs method

Section 4 paragraph 2 clearly states

"before refilling a system after a repair you must say the following

"a blind man would be pleased to see it"

"s** it that will have to do its me darts night"

and finally before turning on the water

"right not sure of this one have the wet n dry ready"

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If at first you don't succeed, remove all evidence you ever tried.

gas4you · Posted: Sun Jun 17, 2007 8:27 pm Post Subject:

__________________
Dave
DRL Gas Services

Agile · Posted: Sun Jun 17, 2007 9:10 pm Post Subject:

Even if it did have an overheat stat the heat exchanger may not be rated to carry a pressure of up to 3.5 Bar.

It needs to have the manufacturers approval to be used in an unvented system.

Tony

Amikom · Posted: Tue Jun 19, 2007 8:03 am Post Subject:

Thanks guys for all the comments - most helpful.
Agreed gas4you, we don't know the leak is fixed yet, so haven't put the ceiling back up yet! Agreed the Magaflo does not affect the ch but thought it may have affected the pipework. Will call the plumber in to find the blockage in the cold feed to the rads and get that fixed.