F&E / Pump position

CG0

Joined
13 Apr 2011
Messages
2
Reaction score
0
Location
Down
Country
United Kingdom
I have a 40 year old oil fired central heating system in a bungalow. The boiler is positioned in a cupboard outside along with an air handler. The house has underfloor hot air ventilation and a vented, direct DHW cylinder. It has recently had 2 radiators added and a new pump.

My feeling is that the system is pumping over and drawing air. Every time the pump starts I can hear air moving in the pipework in the loft and unless I isolate the DHW cylinder then virtually no heat gets to the rads. There are no motorised valves in the system, the boiler is controlled directly by a mechanical time clock and the only room thermostat controls the the air handler. Both new radiators are fitted with TRV's on their returns.

I have just traced the pipework this morning; the flow leaves the boiler rising to the loft, tee-ing off to the air handler, followed by 2 radiators along the way. It then tee's again dropping down to the DHW cylinder and rising further to the cistern. It is a combined F&E in 15mm. Firstly I was of the impression the first connection on the flow should be the expansion. Am I correct? To finish things off the circulating pump is on the return about 6" from the boiler.

To make things more interesting there is an AAV on a short stem off the flow inside the boiler cupboard. I was under the impression these had to be at the highest point in the system or else they can suck air in, not expel it. The plumber who installed the new rads obviously had some problems because at the other end of the loft from the cistern there is a 2m pipe tee'd off the return to one of the radiators which rises to the same height as the cistern and has a stop end (which I presume he cracked open to make some kind of makeshift expansion pipe / guiser!)

Should I be moving the pump to the flow or should I be moving the F&E to the first tee off the boiler? or should I be moving both.

Craig
 
Sponsored Links
The first connection after the boiler should be the open vent.

Its difficult for me to guess whats wrong but a combined F&E covers up most faults.

An auto air vent can be fitted anywhere but they are usually placed at high points on the flow. It would be possible for air to be sucked in from one placed close to the pump. A test would be to place shaving foam over the cap to see if its being sucked in.

Tony
 
I presume it is ok to keep it a combined F&E and just re-pipe it to the first connection? I will probably move the pump too and put it on after. It's a bit tight for space in the cupboard.

Shaving foam is a good trick, I'll give it a go. Worst it can do is clean the system a bit while it's in there.

Craig
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top