The community repair thread

Danny1969

chillidoggy said:

Whilst I didn't actually repair anything per se, this morning I diagnosed the reason why my downstairs heating was only coming on when the upstairs heating was on. I braved the queue at Screwfix, put a new synchronous motor in the 2-way valve for the downstairs circuit, and off she went.

 As the thermostat dial has been so stiff for about 10 years as to be almost impossible to move it without a pair of pliers, I also caved in to the wife's demands for it to be changed, and fitted a new one. Admittedly, I got a 240v belt off the thermostat wires when I forgot it's connected to the mains, but I reckon it was a small price to pay to avoid the wife's tongue-lashing and ear-bending.

All this is particularly satisfying because not only have I managed to avoid calling out a heating engineer on a Saturday, but also the heating usually packs up just in time for the Christmas holidays (most holidays, actually), so I'm hoping I've beat it to the draw this year.

I've got a fault where the hot water won't come on without the heating being on. Even if I tell the hot water to be constant and turn off the heating on the boiler there's no hot water unless the heating is also on. What do you reckon that could be ?

Chris.B

Danny1969 said:

I've got a fault where the hot water won't come on without the heating being on. Even if I tell the hot water to be constant and turn off the heating on the boiler there's no hot water unless the heating is also on. What do you reckon that could be ?

I've had those symptoms on my CH a few times.  The first time I paid a lot of money to have the diverter valve replaced, it cured the fault for a few years.  When the same problem occurred again, I bought a diverter and did it myself in 20 minutes. 

It was only necessary to replace the electro-mechanical driver assembly. The valve part was still functional, this makes it a "dry" job - I don't go near wet plumbing.

boogieman

Danny1969 said:

chillidoggy said:

Whilst I didn't actually repair anything per se, this morning I diagnosed the reason why my downstairs heating was only coming on when the upstairs heating was on. I braved the queue at Screwfix, put a new synchronous motor in the 2-way valve for the downstairs circuit, and off she went.

 As the thermostat dial has been so stiff for about 10 years as to be almost impossible to move it without a pair of pliers, I also caved in to the wife's demands for it to be changed, and fitted a new one. Admittedly, I got a 240v belt off the thermostat wires when I forgot it's connected to the mains, but I reckon it was a small price to pay to avoid the wife's tongue-lashing and ear-bending.

All this is particularly satisfying because not only have I managed to avoid calling out a heating engineer on a Saturday, but also the heating usually packs up just in time for the Christmas holidays (most holidays, actually), so I'm hoping I've beat it to the draw this year.

I've got a fault where the hot water won't come on without the heating being on. Even if I tell the hot water to be constant and turn off the heating on the boiler there's no hot water unless the heating is also on. What do you reckon that could be ?

What sort of heating set up is it? Combi boiler or standard boiler with a hot water cylinder? Any 2 or 3 way valves? 

Danny1969

@Chris.B cheers, that's very useful

@boogieman it's a standard boiler with hot water cylinder, not sure about valves ... plumbing isn't really something I like to get too involved with 

BahHumbug

@Danny1969 I’ve had similar(ish) symptoms on my system, although the cause could be different to yours.  FWIW, I have a standard boiler and hot water cylinder, with two Honeywell motorised valves - one for CH, the other for HW.
The CH valve failed and would not open.  Because of this the boiler would not fire up - it is interlocked so it won’t heat and pump water against a closed valve.  If the HW was on, then there was somewhere for the water to go and the boiler would fire up.  Of course we didn’t get much heating because the circuit was blocked off.
The fix was to replace the motor unit on the valve.

OK it’s not the same as your problem, but you do need to understand the full system layout to diagnose the problem.  But then you knew that, didn’t you.

Whatever control valves you’ve got are likely to be near the HW tank, or maybe near the boiler.

BahHumbug

+1 for this thread BTW.  Loving it.  I haven’t had any fixing fun recently, but when I do I’ll post something up

boogieman

Danny1969 said:

@Chris.B cheers, that's very useful

@boogieman it's a standard boiler with hot water cylinder, not sure about valves ... plumbing isn't really something I like to get too involved with 

Ok well, it could be a zone valve or 3 port valve fault (similar to Chilli’s). Have a look at the pipework near the hot water tank and you might see a motorised valve with wiring going into it. When the cylinder is calling for heated water from the boiler, then the valve should open via a synchronous motor inside. Feel the pipework both sides of the valve and if the bit of pipework going to the tank coil is cold, the valve could be faulty. There should be a little spring loaded lever on the side of the valve which opens it manually, try pulling that over (there could be a detent position to hold it fully open). If the hot water now gets through to the cylinder then the synchronous motor is gone. You can get a replacement from Screwfix and it’s a simple fix, just unscrew the old one and join up a couple of wires... they normally supply a couple of crimp connectors with the new motor.

PS I’m sure I don’t need to tell you, but kill the power to the system before you change out the motor, assuming it is faulty. 

Danny1969

Cheers @BahHumbug and @boogieman ;
I'll have a gander at that tomorrow, house is like an oven at the mo all the time

Emp_Fab

No pics but I replaced all four pots in a cheapo LP clone - not easy as there's no rear access panel and everything has to be done through the f holes.  I realised tonight that I'd wired up the neck pickup to the wrong pair of pots and the bridge to the other (wrong) pair.

Twat.

chillidoggy

boogieman said:

Danny1969 said:

@Chris.B cheers, that's very useful

@boogieman it's a standard boiler with hot water cylinder, not sure about valves ... plumbing isn't really something I like to get too involved with 

Ok well, it could be a zone valve or 3 port valve fault (similar to Chilli’s). Have a look at the pipework near the hot water tank and you might see a motorised valve with wiring going into it. When the cylinder is calling for heated water from the boiler, then the valve should open via a synchronous motor inside. Feel the pipework both sides of the valve and if the bit of pipework going to the tank coil is cold, the valve could be faulty. There should be a little spring loaded lever on the side of the valve which opens it manually, try pulling that over (there could be a detent position to hold it fully open). If the hot water now gets through to the cylinder then the synchronous motor is gone. You can get a replacement from Screwfix and it’s a simple fix, just unscrew the old one and join up a couple of wires... they normally supply a couple of crimp connectors with the new motor.

PS I’m sure I don’t need to tell you, but kill the power to the system before you change out the motor, assuming it is faulty. 

Further to this, my system is pretty basic, balanced-flue boiler, four circuits and no frills.

 The problem I had was that although the 2-way valve for the downstairs circuit was opening, and the thermostat calling for heat, the boiler still wouldn’t fire when just that circuit was energised on the central heating controller, even though it should have.

The issue must have been some kind of issue within the synchronous motor itself that prevented it telling the boiler it was open for business. I’ve rebuilt this system loads of times over the last 21 years, and never had that problem before. The replacement motor sorted it, but I don’t really know why.

Given the above, the synchronous motors are about a tenner each so it could be worth a punt changing them even if they appear to be operating as they should.

Danny1969

Emp_Fab said:

No pics but I replaced all four pots in a cheapo LP clone - not easy as there's no rear access panel and everything has to be done through the f holes.  I realised tonight that I'd wired up the neck pickup to the wrong pair of pots and the bridge to the other (wrong) pair.

Twat.

Another way of looking at that is you wired it correctly and everybody else has wired it wrong ?

boogieman

chillidoggy said:

boogieman said:

Danny1969 said:

@Chris.B cheers, that's very useful

@boogieman it's a standard boiler with hot water cylinder, not sure about valves ... plumbing isn't really something I like to get too involved with 

Ok well, it could be a zone valve or 3 port valve fault (similar to Chilli’s). Have a look at the pipework near the hot water tank and you might see a motorised valve with wiring going into it. When the cylinder is calling for heated water from the boiler, then the valve should open via a synchronous motor inside. Feel the pipework both sides of the valve and if the bit of pipework going to the tank coil is cold, the valve could be faulty. There should be a little spring loaded lever on the side of the valve which opens it manually, try pulling that over (there could be a detent position to hold it fully open). If the hot water now gets through to the cylinder then the synchronous motor is gone. You can get a replacement from Screwfix and it’s a simple fix, just unscrew the old one and join up a couple of wires... they normally supply a couple of crimp connectors with the new motor.

PS I’m sure I don’t need to tell you, but kill the power to the system before you change out the motor, assuming it is faulty. 

Further to this, my system is pretty basic, balanced-flue boiler, four circuits and no frills.

 The problem I had was that although the 2-way valve for the downstairs circuit was opening, and the thermostat calling for heat, the boiler still wouldn’t fire when just that circuit was energised on the central heating controller, even though it should have.

The issue must have been some kind of issue within the synchronous motor itself that prevented it telling the boiler it was open for business. I’ve rebuilt this system loads of times over the last 21 years, and never had that problem before. The replacement motor sorted it, but I don’t really know why.

Given the above, the synchronous motors are about a tenner each so it could be worth a punt changing them even if they appear to be operating as they should.

I think the motor has some sort of position sensor built in, because I seem to remember there’s three or four wires going in? Normally it would only need a feed and return wire, so the extras must do something clever. 

BahHumbug

Yes, the motor unit contains a limit switch, which indicates that the valve is open.  The limit switch only works when the valve is being operated by the motor - if you operate the valve manually, using the little lever, the limit switch doesn’t close.

chillidoggy

Ah, in that case it starts to makes sense. Wonder if the knackered motor was just opening the valve enough for hot water to get past it, but not travelling round far enough to trigger the switch to tell the boiler to fire up?

BahHumbug

Probably....either the motor not able to open the valve fully, or the limit switch failed in some way. I’ve now learnt that if my boiler fails to light and reports (I think) error F10, then I need to check out my valves.

thermionic

OK now I have a project... my Cambridge Audio A4 hifi amp gave up the ghost. I’ve bought a nice new replacement/upgrade but I’d like to fix this as it’s a decent amp. For several years it’s had a scratchy volume pot - not just dirt as it doesn’t change with manipulating the knob. All the hallmarks of a leaky/faulty coupling cap I think. It became a lot worse in recent weeks - loud crackling and popping on start up, twisting or even tapping the volume knob would create more noise and it would eventually pop into life. Apparently Cambridge Audio will supply schematics if you ask them. I could I suppose replace all the electrolytics for not a lot of money but it would be very tedious.

Danny1969

thermionic said:

OK now I have a project... my Cambridge Audio A4 hifi amp gave up the ghost. I’ve bought a nice new replacement/upgrade but I’d like to fix this as it’s a decent amp. For several years it’s had a scratchy volume pot - not just dirt as it doesn’t change with manipulating the knob. All the hallmarks of a leaky/faulty coupling cap I think. It became a lot worse in recent weeks - loud crackling and popping on start up, twisting or even tapping the volume knob would create more noise and it would eventually pop into life. Apparently Cambridge Audio will supply schematics if you ask them. I could I suppose replace all the electrolytics for not a lot of money but it would be very tedious.

It does sound like DC on a pot but you should be able to trace that back easy enough. Often in my experience it can be a mica cap that fails .. not completely short but often in the 3K range so basically turns into a resistor 

crunchman

Talking of Cambridge audio amps, mine is playing up.  Sometimes one or both channels cut out.  It can happen to either channel.  Twiddling the volume knob normally gets it to cut back in.  It normally happens when I first turn it on.  Once it's up and running and been on for a few minutes, it's normally quite stable.  It does have a remote control so there is probably some weird technology in there.

Any ideas to the cause?  Could it be the pot, or something else?

Danny1969

Can you hear a relay click when you turn it on ? a lot of amps have a relay to protect speakers against power on pop and DC faults

roundthebend

My microwave stopped working - literally doesn't power on (no clock, no beeps).
It isn't the fuse in the plug. Should I attempt to fix it myself?