Baxi Bermuda central heating problem.

[Gel]

Baxi Bermuda back boiler Servowarm valve(?) for switching HW/Radiators to H/w only.

The Servowarm valve has been knackered for a few years, we switch the radiators off manually in the Spring, it all used to work wonderfully until recently when the boiler would fire up to heat the HW as normal, but then shut down after 2-3 minutes. The central heating pump ( Grundfos UPS 15-50x ) also started making a low whining noise, we could hear it clearly. Normally it is very difficult to hear the pump in operation.

I assume the pump is knackered ( must be 20 years old ) Is it advisable to replace this pump with a Wickes 'own brand' central heating pump? We have 6 radiators.

The Servowarm switch needs to be replaced, but what with?

Servowarm installed this system 15 years ago and I'm unable to find a drain point, is it easy to drain the system by taking a radiator off? If so, what's the best way of doing this as I can visualize a water based disaster ahead.

Also, before I do this, would it be sensible to drain the H/W cylinder and put Soda crystals in the header tank to descale the H/W system, or am I about to destroy my central heating system, marriage and life.

I have had a quote from a local heating engineers to fix it all for me, but to be honest, even after a lay down in a darkened room, I still don't feel well.

Any advice welcome

Gel.

[Roger Mills]

I'm not sure what a 'Servowarm' valve is - but presume it's just a motorised valve. How many pipes are directly connected to it? Does it also have an electrical connection? When the system is working properly, does the pump run when the HW is being heated without the CH being on, or does it only come on for the CH?

If you answer these questions, we'll be able to understand your system better, and give more sensible advice. If you can take some photos of this valve, and the pump, and your HW cylinder - and upload them somewhere and post a link here - even better!

Meanwhile the pump almost certainly needs replacing. A Wickes pump will probably do if you want a cheaper one than another Grunfos. I don't see any need to touch the HW cylinder - the HW system is separate from the primary circuit - which is the bit giving you grief at the moment. [That's all assuming that you haven't got an 'orrible Primatic cylinder - but that will be clearer if you can provide some piccis].

[Owain]

Probably, and if you're lucky there are valves on each side (and they still work) of it so you don't need to drain down.

Before removing the old pump, note which way the water goes through it, and replace the new one pumping in the same direction.

A new one of the same thing, not necessarily made by Servowarm. Any plumber's merchant should be able to supply "one of these please mate" if you take the old one in.

I'd be inclined to find a low point on the system and fit one of those screw-on washing machine connectors that pierce the pipe. Also get a blanking cap for it because I woudln't rely on them to remain non-leak long-term.

Irrelevant. (Unless you've got a Primatic cylinder).

Not soda crystals. And no point in descaling the system if you don't flush it out, or all the loosened scale will just gunge up the system elsewhere. If you want to flush the system Google this group for Andy Hall's instructions and peruse the Fernox aisle in the plumber's merchants.

Owain

[Fentoozler]

I've come across a couple of Servowarm installations. Check your header tank hasn't run dry. Believe it or not, Servowarm user to install header tanks without cold mains feed (i.e. filled it up before they left by way of a bucket, then scarpered). Unbelievable.

Angus

[Gav]

i have no idea what a servowarm thing m bob is but i reckon your installation will be one of a few standard systems. if it is a 3 port valve then it isnt a big job. just drain down replace and fill up. same for w and s plans. pump will almost be knackered if it has been there 20 years. replace at the same time as valve. you will probably need new pump valves as i have never seen them work again after initial installation. although i have seen them stop weeping after a couple of days for some reason!

hth

[Gel]

"Fentoozler" wrote in news: [e-mail]:

Thanks for all the help everyone, I shall post pics of valve etc. ASAP.

Gel.

[Gel]

Gel wrote in news:Xns98736940DE2CEgelstagelsta@62.253.170.163:

I've taken some pics of pump and valve;

The switch does not have an electrical connection, the pump comes on whenever the boiler is on.

I shall not touch the HW cylinder, I will fit a drain point somewhere suitable and drain. Then replace the servowarm switch and pump ( with new valves, I have been warned ) then Fournox.

thanks again.

Gel.

[Roger Mills]

This so called "Servowarm" valve is clearly a mechanical valve. My best guess is that all it does is to apportion how much of the boiler/pump flow goes to the HW coil and how much to the CH. I certainly wouldn't replace it like for like - even if a replacement were available. A far better solution would be to install a motorised 3-port mid-position valve in place of this crude device, and convert the system into a half-way decent Y-Plan system.

[Gel]

"Roger Mills" wrote in news: [e-mail]:

Thanks Roger, I have changed the pump ( Grundfos UPS 15 50 ) and the system works again. I shall look into a 3 port mid position valve very soon.

Thanks for all the comments,

Gel.