pump problem {i think]

[peterthomas700]

I installed oil fired heating in an old sprawling bungalow 2 years ago and have trouble getting water to the far end of run ,unless i shut off several rads at the boiler end of the system . i have tried balancing system several times but have concluded [maybe incorrectly] that pump just isnt man enough . no problems with air [ pump runs steadily and quietly at any speed setting] . i installed sealed system [unvented ] . system works very well apart from this problem . I used heat loss calcs to work out rad and boiler sizes . I am a level 2 plumber but never got chance to take level 3 .[how i wish i had]
Is it possible to add another pump further up the main 22mm run or can this cause other problems , any advice greatly appreciated

 

[Agile]

You should not need any more pumps!

The solution I expect will lie with the balancing!

Have you looked at the impeller on the pump to make sure its not blocked?

If thats clear then close the lockshields and open them just 1/2 a turn on the rads close to the boiler. See what change that makes and then do the same with the further ones but open them one turn.

Experience is far more important that C&G certs.

Tony

 

[ChrisR]

Your pump could also be running slow, or you could have a sludgy system.
If you're a plumber having a spare pump won't hurt, so I'd try a new one.
COuld be blocked pump valves too.

 

[peterthomas700]

You should not need any more pumps!

The solution I expect will lie with the balancing!

Have you looked at the impeller on the pump to make sure its not blocked?

If thats clear then close the lockshields and open them just 1/2 a turn on the rads close to the boiler. See what change that makes and then do the same with the further ones but open them one turn.

Experience is far more important that C&G certs.

Tony

thanks tony , situation is much improved , i think i may have pushed the limits on length of run of 22mm pipe as bungalow goes off in all directions . also there are some longish runs of 15mm feeding some of the rads . would increasing some of these runs to 22mm possibly help thanks peter

 

[Agile]

15 mm can supply about 5-6 kW.

The answer lies in the balancing!

A common fault in a conventional system is to not use a lockshield on the HW coil. When thats on it hogs all the flow.

I have only met one system which was not possible to retrieve. It had about 8 kW on rads on a 15 mm spur about 10 m long. It would not get more than gently warm but then it was not surprising given the very poor way it had been installed. It was an addition in an extension where the three new rads had been tagged on to the end of a spur of two large ones.

Tony

 

[peterthomas700]

15 mm can supply about 5-6 kW.

The answer lies in the balancing!

A common fault in a conventional system is to not use a lockshield on the HW coil. When thats on it hogs all the flow.

I have only met one system which was not possible to retrieve. It had about 8 kW on rads on a 15 mm spur about 10 m long. It would not get more than gently warm but then it was not surprising given the very poor way it had been installed. It was an addition in an extension where the three new rads had been tagged on to the end of a spur of two large ones.

Tony

thanks for quick response, i will continue with micro adjustments on the lockshields and i will add one to the heating coil [ none of the books i read mentioned that ] although now youve pointed it out i suppose its obvious

thanks again peter

 

[Agile]

Those who write text books and never deal with real customers would say that having no lockshield on the cylinder coil gives minimum recovery time.

Those who deal with customers will say its necessary. In fact only yesterday I went to somewhere with just that problem ( amongst many others. )

 

[mrmarkup]

had same problem in a flat i had in hastings.
ie pipework under sized.
all i did was to run 28mm from boiler to 28mm pump valve (high head pump)and fit 28mm mid position valve.
gate valve on coil return and 28mm heating return boiler to first tee.
worked a treat.