Omega Owners Forum

Chat Area => General Discussion Area => Topic started by: Sir Tigger KC on 16 December 2011, 00:08:50

Title: Central heating buggered....
Post by: Sir Tigger KC on 16 December 2011, 00:08:50
Hi All,

As per title and just as the weather is going to get chilly!!  :(

Its a Potterton Profile 80 conventional boiler.  The heating isn't coming on either on the timer, manually on the controller or the thermostat..... However, the the boiler runs fine when the hot water is switched on, either by the timer or manually.  But here's the thing! When the boiler is running and heating the hot water tank, the radiators are getting hot as well!!

I was thinking that the PCB was knackered but the rads getting hot when the hot waters on has confused me!!  ::) 

Any ideas Peeps??  ???
Title: Re: Central heating buggered....
Post by: paul.lovejoy on 16 December 2011, 00:24:53
we have just had something similar on a job and it turned out to be the pump
may be worth checking ,if the pump is too hot to touch or you cant feel the vibration or adjust the speed it could be that. I will ask our plumber tomorrow/today
Title: Re: Central heating buggered....
Post by: feeutfo on 16 December 2011, 00:27:20
Loopy control unit?
Title: Re: Central heating buggered....
Post by: Osprey on 16 December 2011, 01:02:41
Doesn't sound like PCB to me - the PCB doesn't know or care whether it is being called for heating or for hot water.   Could well be the motorised valve on the central heating side jammed part way open. 

The way it should work is the timer and room stat provide power to open the valve.  When the valve is fully open it hits an internal micro-switch which in turn feeds power ("call") to the boiler requesting it to fire up.  If the valve never opens fully, there will be no signal to the boiler to turn on.  But when the boiler fires up for hot water, there will be accidental flow through the partially open CH valve. 

You can test this theory by locating your central heating motorised valve and operating it manually using the skinny metal lever sticking out of the base of the valve head.  The motorised valves will be somewhere near the main wiring box, and look like one of these
(http://www.plumbnation.co.uk/site/honeywell-v4043b-22mm-2-port-valve/large-v4043b.JPG)
(http://www.plumbnation.co.uk/site/danfoss-randall-hp-28mm-motorised-two-port-valve---actuator-087n661100/large-2port.jpg)

It is frequently the motor part of the unit that fails rather than the actual valve, in which case you can swap in a replacement motor unit without touching the actual plumbing, assuming you are electrically competent.  Otherwise it will be a drain down to fit a complete new valve. 

This assumes you have a separate two-port valve for CH and DHW ("S-plan"). 
Title: Re: Central heating buggered....
Post by: SIR Philbutt on 16 December 2011, 01:34:51
Doesn't sound like PCB to me - the PCB doesn't know or care whether it is being called for heating or for hot water.   Could well be the motorised valve on the central heating side jammed part way open. 

The way it should work is the timer and room stat provide power to open the valve.  When the valve is fully open it hits an internal micro-switch which in turn feeds power ("call") to the boiler requesting it to fire up.  If the valve never opens fully, there will be no signal to the boiler to turn on.  But when the boiler fires up for hot water, there will be accidental flow through the partially open CH valve. 

You can test this theory by locating your central heating motorised valve and operating it manually using the skinny metal lever sticking out of the base of the valve head.  The motorised valves will be somewhere near the main wiring box, and look like one of these
(http://www.plumbnation.co.uk/site/honeywell-v4043b-22mm-2-port-valve/large-v4043b.JPG)
(http://www.plumbnation.co.uk/site/danfoss-randall-hp-28mm-motorised-two-port-valve---actuator-087n661100/large-2port.jpg)

It is frequently the motor part of the unit that fails rather than the actual valve, in which case you can swap in a replacement motor unit without touching the actual plumbing, assuming you are electrically competent.  Otherwise it will be a drain down to fit a complete new valve. 

This assumes you have a separate two-port valve for CH and DHW ("S-plan").

Totally Agree - pump will go on and off with adjust of thermostat to check it
Title: Re: Central heating buggered....
Post by: Lazydocker on 16 December 2011, 02:38:45
Pump or 3 way valve :y
Title: Re: Central heating buggered....
Post by: freecall666 on 16 December 2011, 04:08:55
check the termostat we had fault with ours last year and it was that, could here it click when moved it but heating would not come on, so got spare one out and replaced it, heating worked then.
Title: Re: Central heating buggered....
Post by: paul.lovejoy on 16 December 2011, 07:08:26
ditto what you boys are saying about the motorised valve the job we are doing is very similar and i thought it was the valve at first but the plumber thinks it is the pump we wil find out this morning when he carrys out the work could be pump and valve :o
Title: Re: Central heating buggered....
Post by: Marks DTM Calib on 16 December 2011, 08:19:19
Its not the pump as the overheat trip on the boiler would have kicked in whilst heating the water.

It will be the valve, either the micro switch or the motor.

You have to remember that neither the timer nor the thermostats directly actuate the boiler, this is triggered by the valve. The sequence of events is the timer calls a demand, the stat confirms its requried, the vlave moves to the correct position which in turn closes a micro switch in the valve to call for the boiler to fire.

Title: Re: Central heating buggered....
Post by: Auto Addict on 16 December 2011, 08:47:15
Its not the pump as the overheat trip on the boiler would have kicked in whilst heating the water.

It will be the valve, either the micro switch or the motor.

You have to remember that neither the timer nor the thermostats directly actuate the boiler, this is triggered by the valve. The sequence of events is the timer calls a demand, the stat confirms its requried, the vlave moves to the correct position which in turn closes a micro switch in the valve to call for the boiler to fire.

As the man says :y
Title: Re: Central heating buggered....
Post by: Sir Tigger KC on 16 December 2011, 09:27:37
Thanks for the answers  :y

The heating came on fine this morning, nice and toasty!!  :)

The pump is whirring away nicely and while it's hot to touch, it's not red hot.  I did wiggle the little lever on the motorised valve last night so maybe I freed it up.....  ???

I'm wondering whether to flush the system with a chemical cleaner like Fernox or Sentinal? Might be some crap floating about which jammed the valve?  ??? 

Thanks again!!  :y :y :y
Title: Re: Central heating buggered....
Post by: millwall on 16 December 2011, 10:06:18
just done mine  chemicals in 2 weeks ago  and powerflushed the system this morning  made a big difference   :y
Title: Re: Central heating buggered....
Post by: Terbs on 16 December 2011, 14:06:47
My Central Heating packed up yesterday...thought it was the programmer, but after taking the body off....no power on the live side. Traced the wiring to a Honeywell junction box...blown F2A fuse. :(
However, Honeywell care, as in the corner of the box is a spare fuse. :y
Luv ya Honeywell....up and running again...swmbo impressed...brownie points :y :y :y
Title: Re: Central heating buggered....
Post by: Marks DTM Calib on 16 December 2011, 14:59:16
My Central Heating packed up yesterday...thought it was the programmer, but after taking the body off....no power on the live side. Traced the wiring to a Honeywell junction box...blown F2A fuse. :(
However, Honeywell care, as in the corner of the box is a spare fuse. :y
Luv ya Honeywell....up and running again...swmbo impressed...brownie points :y :y :y

The question ahs to be though.......why did the fuse blow!

Its either the wrong rating and is being aged or there is an intermittent fault.....
Title: Re: Central heating buggered....
Post by: Kevin Wood on 16 December 2011, 15:25:04
I'm wondering whether to flush the system with a chemical cleaner like Fernox or Sentinal? Might be some crap floating about which jammed the valve?  ??? 

More likely to be the microswitch in the valve, IMHO. Same happened to ours, so if it's the normal controls that get fitted with a Profile I'd say it's likely. Same microswitch as the door locking motor on an Omega so I had a spare. :y

But.. you can normally check operation of the valve as there's an indicator somewhere on the body and also a manual operating lever. You should hear the microswitch click as it opens.

The PCB in the boiler will fail some other day day, but lives for now. :D
Title: Re: Central heating buggered....
Post by: paul.lovejoy on 16 December 2011, 17:29:19
Glad your all sorted Tigger well heatings working again great to see all the good advice when you need it tis what i love about OOF :y :y

hot flush, what am i like :-*
Title: Re: Central heating buggered....
Post by: Pitchfork on 16 December 2011, 18:56:27
I too have a Potterton Profile 80 & had the same problem
Called in a Plumber at huge expense who squirted WD 40 on the Honeywell 3 way valve shaft afer removing the solonoid
A quick couple of twists back & forth with a pair of pliers & it all worked again
I expect that is your problem
Title: Re: Central heating buggered....
Post by: TheBoy on 16 December 2011, 19:02:51
If the valve goes sticky, or the coils burn out, its only ever a temp fix. Ultimately, you will have to replace the valve.  Easy job, but has to be (partially) drained.
Title: Re: Central heating buggered....
Post by: Sir Tigger KC on 16 December 2011, 20:55:48
Thanks for all the replies and advice!  :y

The heating failed again this evening so I flicked the little switch on the valve and bingo she fired up!!  ;D  I think I'll try Pitchfork's plumbers method first and see how she goes....  ::)
Title: Re: Central heating buggered....
Post by: Marks DTM Calib on 16 December 2011, 22:13:41
Thanks for all the replies and advice!  :y

The heating failed again this evening so I flicked the little switch on the valve and bingo she fired up!!  ;D  I think I'll try Pitchfork's plumbers method first and see how she goes....  ::)

Lol, not such a great plumber though, a bit of lube is not actualy addressing the fault
Title: Re: Central heating buggered....
Post by: millwall on 16 December 2011, 22:18:41
as already said dont bother with the bodge  wont last long  generally a lot of plumbers will do a bodge as people want to save money  i get loads of calls to repair bodge jobs  hence the reason i mainly do commercial work    shame you werent local tigger would of done a freebie for you
Title: Re: Central heating buggered....
Post by: paul.lovejoy on 16 December 2011, 23:09:18
a freebie from a plumber :o :o you will be saying you clear up your own mess on site next ;D ;D ::)
Title: Re: Central heating buggered....
Post by: millwall on 16 December 2011, 23:20:00
a freebie from a plumber :o :o you will be saying you clear up your own mess on site next ;D ;D ::)

now your taking the mick paul  that will never happen ;D
Title: Re: Central heating buggered....
Post by: paul.lovejoy on 16 December 2011, 23:24:25
lmao tell me about it feel like a plumbers bitch at times ;D ;D ;D
Title: Re: Central heating buggered....
Post by: millwall on 16 December 2011, 23:25:43
lmao tell me about it feel like a plumbers bitch at times ;D ;D ;D
;D ive heard many trades say exactly the same ;D ;D
Title: Re: Central heating buggered....
Post by: Sir Tigger KC on 17 December 2011, 14:12:59
as already said dont bother with the bodge  wont last long  generally a lot of plumbers will do a bodge as people want to save money  i get loads of calls to repair bodge jobs  hence the reason i mainly do commercial work  shame you werent local tigger would of done a freebie for you

Many Thanks Millwall!!  :y  As said, I'll chuck some cleaning chemicals in the F/E tank and change the valve when I flush the system  :y
Title: Re: Central heating buggered....
Post by: Terbs on 17 December 2011, 14:35:02
My Central Heating packed up yesterday...thought it was the programmer, but after taking the body off....no power on the live side. Traced the wiring to a Honeywell junction box...blown F2A fuse. :(
However, Honeywell care, as in the corner of the box is a spare fuse. :y
Luv ya Honeywell....up and running again...swmbo impressed...brownie points :y :y :y

The question ahs to be though.......why did the fuse blow!

Its either the wrong rating and is being aged or there is an intermittent fault.....

Thats the question I always ask, mate, must be a reason. The old and new fuse fitted are correct ...F2AL, which are 'Glass Quick Blow' as stated in the control box.
Unit is two years old. There still could be a problem somewhere, only time will tell  :y
Title: Re: Central heating buggered....
Post by: Martian on 17 December 2011, 19:09:42

Thats the question I always ask, mate, must be a reason. The old and new fuse fitted are correct ...F2AL, which are 'Glass Quick Blow' as stated in the control box.
Unit is two years old. There still could be a problem somewhere, only time will tell  :y
Could be something as simple as old age or there was an intermittent spike on the mains at the time, how the fuse blows gives a good indication of whether there is a fault or not as well.

PS

The letter L in the fuse code denotes low breaking capacity as well as it being quickblow
Title: Re: Central heating buggered....
Post by: Kevin Wood on 18 December 2011, 00:16:08

Thats the question I always ask, mate, must be a reason. The old and new fuse fitted are correct ...F2AL, which are 'Glass Quick Blow' as stated in the control box.
Unit is two years old. There still could be a problem somewhere, only time will tell  :y
Could be something as simple as old age or there was an intermittent spike on the mains at the time, how the fuse blows gives a good indication of whether there is a fault or not as well.

PS

The letter L in the fuse code denotes low breaking capacity as well as it being quickblow

Yep. If the glass didn't break or at least go black too, you weren't even trying. :D
Title: Re: Central heating buggered....
Post by: Pitchfork on 18 December 2011, 18:32:13
If the valve goes sticky, or the coils burn out, its only ever a temp fix. Ultimately, you will have to replace the valve.  Easy job, but has to be (partially) drained.
Well FYI it occurred 4 years ago & the problem has not returned since so in my case it was not a temporary fix