Fitting a second central heating pump?

[brokenboiler]

Is possible to put a secondary central heating pump on the downstairs circuit?

The reason I'm asking this as i said in my earlier thread the radiators are cold downstairs. I've recently had all the pipes changed downstairs to 15mm all through and had a couple of new radiators put on. If you shut them all off downstairs and open them one at a time they start to get warm.

Now of my boiler they're a 22mm feed and return, but there's only about 7 foot of 22mm and then it all goes to 15mm downstairs?

What I'm asking is is it easier to fit a secondary pump downstairs or will this create pressure problems or should I make it all 22mm from upstairs to downstairs and only tee it off to the radiators in 15mm?

Thanks in advance

 

[buffy27]

how many rads upstairs and down.what size boiler and pump.have u got manifolds, do u have a copper cylinder or combi.open vented or pressurised heating .motorised valves.

 

[brokenboiler]

I have a combi boiler.

The systems presserized.

I have 6 radiators downstairs some doubles and 4 radiators upstairs.

My boiler is a worcester 240 combi. All downsatirs was done in 15mm and upstairs is 15mm with microbore coming of it. It's piped up as a two pipe system.

It's also a grungfos 15/60 pump on the boiler.

I'd like to know it i'm either gonna have to get a higher out put boiler or will i get away with just swapping the 15mm for 22mm and just having 15mm tail ends into each rad. I suppose the question is will the boiler handle all those radiators?

 

[buffy27]

that boiler has outputs of between 9.2 and 16 kw.possibly enough for ten rads as u have described.the pump u mentioned is a 6 m head pump which should b plenty.the piping would definitly b fine.tough one to call without seeing it. try flushing system out and turn up pump revs. buffy

 

[PipeStrangler]

BB - that pump should murder the circulation on your relatively small (10 rads) system. Once you get it working you'll find you only need it to be on pump speed 1.

So NO - you don't need a 2nd pump on it.

What type of valves do you have. If TRV's what make. I have experience of some makes sticking shut. Is the pipework hot but the rad cold at any of the upstairs rads ??

Are the heating circuit motorised valves wired up and opening properly ? They have a manual lever, so fix them open to make sure.

However, it sounds more like an airlock or sludge problem to me, unless your plumba has mixed up his circuits.

You're on a combi, so no DHW problem.

Make sure the lockshield valves are all open (other side of rad from TRV's)

Shut off all the trv's but one, perhaps one which is working downstairs. Ramp the heating up good and hot, with the boiler stat set to Max, for 5/10 mins until that rad's hot.

Open next rad's TRV first, then shut down the one which was open. Go round the whole system doing this, 5/10 mins per rad, or until rad is good and hot.

Listen for air collecting at any higher level rad - usually one of the upstairs rads, dependant on circuit layout, and bleed that out.

Is there an auto air vent on the boiler, or elsewhere in the system - make sure that's open and venting...

Keep the system pressure topped up following venting rads or auto air vent releasing air.

Systematically work round the system one rad at a time. Downstairs first, then upstairs.

Hopefully you should then achieve heat at each rad, if only individually. This should clear airlocks, and prove whether there are sticky TRV's or a sludge blocked circuit.

Make sure the boiler doesn't trip out on over temp cut out - if it does allow 5 mins circulation then re-set thermal cut out and try again.

If they all work individually then open all upstairs trv's - do they now all heat.

If so then open all downstairs rads as well -how's that ?

Hope this helps - Let me know how you go on.

If all else fails refer to plan B.


Rgds - Jon.

 

[brokenboiler]

A finally got a plumber who seemed to know a bit more than the one who changed the pipes and put on the radiators. He basically said my radiators should be bouncing off the wall with what the boilers kicking out.

He went through the motions af bleeding it and trying to force the hot water downstairs, but my boiler won't stay on log enough beofre it trips out on over temperature

We pulled the someof the floor boards up to trace how the circuit ran up stairs and found that there was more 22mm pipe thatn i'd originally assumed.

We tried to force flush the system with all the radiators turned of but it didn't make much difference or so i thought. Now three of the big radiators downstairs are starting to get luke warm but very slowly.

He's coming back on monday to sort the problem out. He thinks it's the return pipe going back upstairs, where it tee's back in to the 22mm it braches off to another couple of other radiators so it could be blocked or resticted. We're gonna try to by-pass the reurn pipe and hook a hose up to fill loop on the return hose on the boiler.

I can hear air bubbling in the radiators upstairs and I bled one tonight and loads of air came out. The DHW is full of air as well. When I have a shower or fill the baby's bath at night the boiler trips out and I have to bleed the pump. I think the auto air bleed valve in the boiler is stuck. So that's another job

Will keep you posted cause i'll be glad when it's sorted. I wonder if i can charge the plumber for helping him

 

[mrlennie]

Very interesting. can i ask why not just drain the system down in the first place? im in training and wondering what i would do in this situation.