Constant Airlocks

[Plamber]

Hello all.

The system is an open vented system with the cold water tank 5" above the cylinder in a small cupboard so there is no way of removing them (must have been built in). it is heated by immersion heater.

The thing is, its airlocking every couple of days, the woman said its been like that for 8 years and has only now tried to get it sorted.

What i have tried so far is emptying both tank and cylender and filling up from washing machine valves, from bath taps, WHB taps and kitchen taps. getting everything working for a few days then the pressure on the hot water drops to very slow. the kitchen and bathroom are on different sides of the flat and all the pipework seems undamaged (no kinks,dents). I even had another and very experienced plumber with me today and he was confused with it. his suggestion was some kind of flange, something ive never fitted or used before.
ADVICE PLEASE.

thanks in advance


I have also increased the hight of the vent pipe as much as possible.

 

[macplumb]

Dose the hot water distrabution pipe rise slightly when it leaves the cylinder?

 

[Plamber]

slightly yes, not more than 2 inch though.

 

[macplumb]

Is there a pump on the system for a shower or to increase flow?

 

[Plamber]

no, its a very basic system. flat doesnt even have a shower.

 

[Plamber]

BUMP

Just bringing bck to top

 

[secret squirrel]

Hello Plamber,

I've been following this post but I haven't got any useful to contribute but I don't understand your last post.

I don't understand why the customer wants something doing now after such a long time, has it got worse for the customer!

Is it possible (I really don't know) that there is a dodgy gate valve somewhere creating a problem or a tap, as I'm typing this I'm thinking 'you'd see a leak though"

 

[Plamber]

She lives in a rented flat from a housing association. the previous owners ignored her when she mentioned it. but the housing association i work with have now purchased the whole housing scheme and pride themselves on prompt repairs.

The only thing i can currently think of is fitting an unvented cylinder. but that seems pretty excessive. is there some kind of flange or fitting i dont know about that i could fit to the vent pipe??

 

[secret squirrel]

I can't think of anything, hopefully, someone else will. Have you spoken to your local merchant about fittings etc. I find them extremley helpful.

 

[moony]

not sure really does the cwsc fill up quickly enough ? no blockage? maybe when filling the bath its emptying quicker than filling the cylinder,

an unvented ? why not a combi ?

 

[Plamber]

the cold water tank is massive and definatly has enough water in it.

Its an open vented system, no combi due to the block not having gas. its electric heating they have.

know abput any kind of fitting i could fit to the vent pipe to stop it drawing in air.

 

[WHPES]

If it is the rate of fill of the cistern, you could change the ballcock to a 3/4" one.

 

[Puddle]

When you leave after back filling all pipework full of water and running nicely,so air is getting in from that point,as said tank may be big enough but what about refill,she is in flat ,does tank feed other flats as well causing to empty
Is supply pipework to cylinder from tank to her flat only or feed others,if so could be another flat could be robbing her supply
Also could vent pipe be blocked up,check clear
Presume when you back fill pipework you let run for 5 mins or so
Does she take baths,if so ask her to fill slower and see if then ok

 

[Plamber]

i've filled a few baths after back filling the system each time ive done it. and then the pressure is fine for a few days, one time i did it it was fine for 2 weeks!

As for the tank, each flat has their own one and this one is definatly big enough for her and fills up fast enough. there is no shower in the property.

 

[moony]

there a valve that can be fitted to the vent to allow air out but not back in? im sure ive heard of this but i cant recall ever seeing one. maybe it would help. non return air valve - not sure on the legallities of fitting one of these to the vent - would be pretty dangerous if it failed.