I’m being quoted £x,000 to replace this!

[belfry]

We live on a remote farm with our house and other buildings being heated by a 10year old biomass boiler system.

We’re being told that our control panel needs replacing and that it is no longer available as many of the components are now obsolete.

A whole new control panel is likely to cost several grand and there is no idea of how long delivery might be.

I live in East Anglia and wondered if there was anywhere trusted to take the motherboards that I have removed?

We have no heating and no hot water and my family is not very impressed. The heating engineers don’t seem to be able to think beyond replacing the whole control unit.

Any suggestions very, very welcome! I attach some photos to give you some idea of what we’re dealing with.

[belfry]

Photo

[belfry]

Relays

[DavidAlfa]

I know nothing about this board, but what's the fault? Nothing obviously wrong at first sight.
Any electronics guy should be able to make some basic checking, testing those relays, power regulators, replacing capacitors if required... Even you could do it yourself if you have some soldering skills.
As long as the eeprom/flash memory is OK, the rest should be replaceable!

[belfry]

Thank you for your reply.
The boiler system keeps stooping and displays “Motor fault heat exchanger”, but the motor has been tested and seems to be working fine. I’m worried that the engineers are just suggesting throwing money at the issue (my overdraft!). They are adamant that the manufacturers will only supply a whole new unit due to some parts not being available any more.
Any suggestions of where I can take it? I’m off the Cambridge on Monday and I guess that there are likely to be some people or firms they who might help.

[Terry Bites]

Does the motor actually start turning when the system demands it?
If not, it could be a motor drive or switching failure on main PCB- that could be as simple as a duff relay.
Try and trace that relay. Can you feel it (light touch) clicking in or out?
Unsolder it and test it. Relays are cheap and easy to source.
It could also be a proplem with valves failing to open, again check apropriate control relays.
Pressure switch?

If its not the motor it maybe a sensor attached to the motor that's faulty. Something in there checks its running. A flow sensor?
The sensor input circuit on the pcb may have problems.
google maps "electronic repairs near me".

[bookaboo]

The company I work for used to have a contract to service these types of PCB. There’s an inherent design flaw in the PCBs, the relays are under rated for the application…. Basic stuff but the designer got it wrong.

It will only be one or two of the relays giving trouble , a good technician will be able to tell you which of them isn’t working.

There may be some local electronics repair shop that can replace the relay(s) for you. If not search for Electrotech Solutions….. based in uk and do a decent job.  Just make sure to tell them it’s relays only.

Bad news is it will happen again in 18 month. We advised our customers to fit proper contactors on the functions that were burning out.

This design flaw is endemic in these systems, and the companies responsible are benefiting from their own errors.

[bookaboo]

The relays I refer to are the orange ones.

Also if you are really in a panic see if radwell or lektronix have a repair shop local to you.

[Ian.M]

No-one can fully diagnose the motherboard without a test jig that pretends to the motherboard to be the rest of the system, faking sensor inputs and showing the tech what outputs the board is activating.  However independent component level repair has been in a severe decline in the UK for several decades so the chances of anyone other than the manufacturer having such a test jig are minimal, and they've told you they no longer support it.  To some extent, the system is its own test jig, but that means you need a field service tech with component level repair experience, who (if you can even find one) will charge an eye-watering callout fee and hourly rate with no guarantee of success. 

As David and Terry have pointed out, even without a test jig, easy faults like a failed PSU or a burnt PCB mount relay can probably be found and fixed by a good independent repairer, *IF* you can give a good enough fault description, which needs to be specific to which outputs are bad, but few customers are capable of that, so most repairers will be very reluctant to accept such work on a board they aren't familiar with.  If you have *ALL* the system documentation and wiring diagrams with you, it *may* help overcome their reluctance.

[voltsandjolts]

The boiler system keeps stooping and displays “Motor fault heat exchanger”, but the motor has been tested and seems to be working fine.

The photos suggest this system is around 14 years old. Is the pump the same age? Are you really sure the pump is good? I mean, could it be that after some hours running the pump gets somewhat hotter and perhaps starts to seize, draw more current and trips out the system as you describe? If not too expensive, I'd replace the pump first, just to guarantee it's not the problem.

[jpanhalt]

There is a lot of paperwork along side it.  Does it give error codes to help localize the fault?

I have what we call a hydronic heating system.  It uses hot water to heat the house and the domestic hot water is produced by a heat exchanger with the heating water.  There's a boiler, 2 pumps, lots of water pipes.  I use propane for the power.  Originally there was both an indoor wood burner and outside wood burner that added 2 more pumps.  In other words, aside from my heat source, it might be similar to your system.

My control panel went bad about a week after I bought the place in 2010.  It was cycling on off and no heat.  Similarly, it was obsolete, but a new panel was only $200, it was freezing outside, so I got it.  Later, I took apart the old control panel  It was less complicated than yours (house was built in 1993, but similar.  The solid state stuff rarely fails.  The problem was the small "logic" relays -- about half the number of orange things on your board. 

Sorry for the long lead in to my suggestions:   
1) Those relays look like standard footprint control voltage level relays.  Identical brands may not be available, but there are inexpensive substitutes.
2) If you cannot localize the fault to a single circuit/couple of relays, buy a bunch.  Otherwise, buy what you need to replace them and replace suspect relays in that motor circuit.
3) The motor may be fine, but there is probably a boiler fan and other things that need servicing.  My boiler fan gets oiled once a year.  A replacement is about $100.
4) Check that the pumps are working.
5) My system had a bypass valve between boiler input and output.  Its purpose was to give a quick temperature rise in the boiler and reduce water condensation in the flue.  At 30 years, it stuck open.  I got rapid cycling, an overheat situation, and the house temperature rise was limited to only about 10° above outside ambient.  I removed the valve and added a drain to the flue.  It has a water trap to prevent gases from entering the house.

If your system is like my system, I would look at #5 first, then #1.  Solid state devices rarely fail.  Mechanical (e.g., blowers, relays, and valves) are the most likely failure points.

[mikeselectricstuff]

I'd agree that a relay contact, or possibly coil,  is a fairly likely cause.

I'd use a meter to trace the motor connection to find which relay it goes to. See if that relay clicks on when it should and check the voltage across the motor.

You may even find that tapping the relay when it's supposed to be on may show some life and/or some visible arcing inside the relay.


If it's not something you want to tackle yourself, the only thing I can think of is maybe talk to a small electronics assembly house - they will usually have at least one test engineer who could probably sort you out if asked nicely

e.g. https://protronics-uk.com/about-2/


 

[jonpaul]

Find a licensed electrician in your area familiar with industrial controls, contactors, 240/480VAC safety.

All the relays and contactors are STILL made and available.

Bon chance,

Jon

[mikeselectricstuff]

Find a licensed electrician in your area familiar with industrial controls, contactors, 240/480VAC safety.

All the relays and contactors are STILL made and available.

Bon chance,

Jon

The avarage uk electrician (we dont have licensing here) would not have a clue about this sort of stuff

[DavidAlfa]

If you have any small 5/12V wall adapter, a cheap soldering iron and a basic multimeter, you could do this yourself within an hour or so, it's very easy, any doubts will be quickly solved by forum users .

Meanwhile, post some high-detailed top/bottom pictures of the relay board!
Might sound dumb, but have you tested the fuses?

[belfry]

Here is a photo of the back of the board containing the relays. I have ordered 13 of the orange ones RT314024 and 6 of the black ones MP240D4. I am happy to replace all of these myself (although I will have to google how to remove a multi pin relay with just one soldering iron!).

[jpanhalt]

Those Crydom MP240D4 (black) relays are solid state relays.  I don't know what their failure rate is.  Mechanical relays have a high rate of failure.

[Twoflower]

There is a black solder joint (top middle of the underside picture). Can you check if the solder joint is OK? That doesn't look good.

If you're lucky that could be the reason for your problem.

And check the blue devices close to the SSRs on the right side, there seems some black snot there. Especially the upper one.

[DavidAlfa]

Soot will stick to high voltage traces, looking like this, though nothing being actually wrong.
If it was a hotspot it would look a lot worse!
To remove the relay, get a solder sucker, desoldering pump or whatever it's called:

[BillyO]

There is a black solder joint (top middle of the underside picture). Can you check if the solder joint is OK? That doesn't look good.

If you're lucky that could be the reason for your problem.

And check the blue devices close to the SSRs on the right side, there seems some black snot there. Especially the upper one.

Yup.  2nd pin of the X3 connector.

There also seems to be a bit of soot on the board.  What was under that board?

[belfry]

Here is a close up of that black pin on X3. Is there a simple way to test it for continuity? I have a couple of multi meters.

[belfry]

That joint was over this area. Bottom rhs.
This is getting exciting!

[DavidAlfa]

Can't see that last attachment? Getting 404 error.

[BeBuLamar]

Thank you for your reply.
The boiler system keeps stooping and displays “Motor fault heat exchanger”, but the motor has been tested and seems to be working fine. I’m worried that the engineers are just suggesting throwing money at the issue (my overdraft!). They are adamant that the manufacturers will only supply a whole new unit due to some parts not being available any more.
Any suggestions of where I can take it? I’m off the Cambridge on Monday and I guess that there are likely to be some people or firms they who might help.

I would try to find out how the board knows if the motor is faulted. If the motor is controlled by a single contactor then it's fairly easy to find out how the board determing if the motor is bad. We can go from there. if that is the case I am afraid the problem is still there after you replace the board.

[belfry]

Try this