Glowworm spacesaver-problem continues...

[bigbrother3269]

Hello again all,well as an update to my origional posts i've had the system powerflushed but made little differance.i've still got a problem(or not) in that the boiler runs for abuout 8 to 10 mins then cuts out,i've noticed that when the boiler cuts out turning the room stat up further has no effect,but turning the cylinder stat up fires it up straight away.I've changed the room stat again today and checked the 3 way (installed last month with pump) and all appears to operate correctly.Question is should i still get live feed to cylinder stat and HW call when heating only is selected on the controller,also it was mentioned to me about Heat transfer paste on the boiler stat thermister-this is dry in its vial-will this have any effect on the problem i'm getting?-could it be the boiler stat itself playing up as it controls the gas valve??-any way of testing this please??

 

[stem]

I didn't see your earlier post, but it sounds to me that it could be working properly.

The boiler is designed to heat water, and that's it. When the water in the boiler is at the temperature set on the boiler thermostat, the burner goes off, until the water falls below the set temperature and then it fires up again. That's why when you switch on the hot water, it fires up straight away as cooler water entering the boiler turns it on again.

Boilers are generally oversized for the system they are attached to, and if the burner kept going continually, then the water would actually boil. The thermostat controls this.

If the flow pipe from the boiler is hot, then the boiler is doing its job. To check, you can buy a clip on thermostat from most DIY sheds for £10-£20, clip it on the flow pipe from the boiler and check the temperature. If it more or less corresponds with the temperature set on the boiler thermostat all is well (with the boiler at least)

If the water leaving the boiler is as hot as it should be, but the radiators aren't you have a problem with the system somewhere else.

The room stat doesn't control the temperature of the water leaving the boiler. Think of it as a simple on/off switch. It switches off the radiators when the room reaches the set temperature, and then switches the radiators on again when the room cools.

 

[bigbrother3269]

Thanks for your reply Stem,i was suspecting that this may be the case,i'll bring you up to speed though.i was asked to have a Quick(!) look at this sytem for a neighbour-its primary problem was lack of circulation round the rads coupled with a temperatur differance between upstairs and down,after a bit off a check over the rattleing pump was replaced as was the semi siezed 3 way valve,i got a mate to powerflush the system(he owed me a favor) as its 10 mm microbore and i've hit sludge before in these,we've now got heat all round but the boiler still cuts out just before the downstairs rads get really hot(like upstairs)-i changed the hall stat and was considering moving it to front room instead(coolest room),incidently all rads bar one have TRV's fitted.the only reason i was thinking about the boiler stat was i wondered if this could be overiding the room stat-i'm staring to wonder as well if everthing is ok and its always been like this-but the neighbour has never noticed how long the boiler runs for-in 20 odd years....

 

[stem]

I think the system needs balancing. Most faults like this are down to the installation the boiler is connected to rather than the boiler itself. Unfortunately it often seems to get the blame. If the upstairs radiators are hot then the boiler is producing hot water, the system isn't distributing it to the downstairs radiators properly.

There's lots of information on here about how to balance a system, try the Wiki and FAQ's.

 

[Ihavenojob]

Does the heating run independantly with the water off? If not it sounds like boiler is only being fired by hot water so could be wiring or cyl stat fault

 

[Agile]

Further confirmation that the OP should have continued the original thread so that we could read the history and see the whold picture..................

 

[bigbrother3269]

Can i thank Stem and Ihatemyjob for your reply's again,Stem i was thinking along the lines of balancing the system-so i did it again today whilst replacing the 3way with another as i noted last night no movement on the lever when selecting between DHW and CH and OFF,i know it was only 3 weeks old but after speeking to salus they said poss faulty unit-anyway made little differance-nor did a balencing session as the rads below are now worse!-you'd almost think major blockage or air but trust me i've bled/drained it till it hurts!.I've noticed this system appears to have a gate valve in some 15mm pipe-off the CH loop as a bypass?-but given this is hot both sides i figure it aint siezed.In answer to does it fire on heating only-yes but for about 5-8 mins then off,increasing the roomstat at this point makes no impact-hence why i was wondering about the boiler stat,i did consider the cyl stat was overiding but after checking appears to be ok-if i de-wire it will the system still run?-and should i get a power feed to the cyl stat even when on heating only?
Anyone got any more ideas??
Agile-sorry mate but i'm not sure how to pick up an old thread and move it to the front again-in order so it gets seen,really sorry about this.

 

[stem]

I've noticed this system appears to have a gate valve in some 15mm pipe-off the CH loop as a bypass?-but given this is hot both sides i figure it aint siezed.

This by-pass valve. It would normally be just cracked open slightly to allow a small amount of water past. If it's fully open the majority of the water will take the easy route through the by-pass rather than the resistive route via the radiators. Just a thought.

i'm not sure how to pick up an old thread and move it to the front again.

You simply find the old thread and click on "post reply" (as you have been doing with this post) and the system will then automatically put it at the front. Don't do it now though, or you will really confuse things.

 

[bigbrother3269]

Thanks again Stem for your reply-well this valve is fully open and from what i understand always has been,i might try to close it down a bit later,having said that i've done a search on here about bypass valves and found quite a bit-and following yesterdays session re the 3 way i was told last night that all rads hot now but boiler is still doing its usual 10 min thing,i'll check it later but may have to assume its quite happy(!) as it is,i'll keep this thread running to update how things progress.

 

[Agile]

If you have a three way valve then you dont need any bypass valve ( unless you have TRVs on ALL the rads!

In that case turn it off!

Tony

 

[Agile]

i'm working on a property which has a potterton 10-16 boiler,randall 4033 programer and microbore pipework(!),its a 3 bed semi-boiler in kitchen-hot tank on landing-cold tanks in loft.we were asked as part of the works to add a radiator in the conservatory and fit trvs to some of the existing rads,work was duly completed and now the problems...i got a feeling that all was not well before we started(just not told this by customers!!)
....

This seems to imply that you are some kind of plumber or builder!

So is this Glow Worm also a job for a customer?

If this is the case then its better to be open about the situation at the outset!

Tony

 

[bigbrother3269]

Tony,thanks for your reply(S),i should have mentioned that the system has TRV's fitted by the previous plumber on all rads bar the towel rail in the bathroom-and thankyou for the advice regarding the bypass valve.
In respose to your second post i've never indicated anything else-i run a small buisness renovating property inc kitchen/bathroom refits etc,i work alongside several tradesmen like myself and whilst i have over 20 yrs general plumbing its only been in the last couple of years that central heating has come to the fore,i've got a gas safe fitter-in fact make that 2 fitters on tap,but in fairness show them anything other than a combi and there both lost-as are several guys i know in the local area.i'm midway through a course now and figure that as my old plumbing master is now departed the best way when i'm unsure or possibly overlooking something is to ask-because the course i'm on which gives me several bits of paper at the end for my 6k has nothing to do with older systems,so i prefer to ask seasoned guys like yourself for help- i'd also like to point out i know my limitations but i'm old school and know the only real way to learn is by hands on the job,it has been pointed out to me by one of my gas safe guys that i do seem to attract these older systems but hey-customers/neighbours we help them all. hope this clears things up a little.