Ongoing Central Heating Problems!

[Frustratedhouseowner]

Hello folks,

My first post and I'm afraid it's a long one! I'm looking for some advice in an ongoing central heating problem I've been having since the start of December.

I've got a Y plan Honeywell central heating system which is about 18 years old. The system started out with a ST1591 programmer which allows HW, CH or a combination of both, a T6360B room thermostat in the living room, a L641A Cylinder thermostat and a V4973A motorised mid position valve.

I have a service contract with a Glasgow based healthcare company whom I will not name and I contact them at the start of December because we were having an intermittent fault where the boiler would not fire when the central heating was switched on, but would work fine when the hot water was switched on.

The company sent out engineer 1 who couldn't get the system to fault but suggested that as the boiler was working for hot water, the problem lay with either the room thermostat or the micro switch in the mid position valve (the micro switch was replaced about 2 years ago for a similar fault). However, as he couldn't get the system to fault he couldn't order any parts and suggested that the next time it happened, I should turn the room thermostat and if I heard an audible click, the problem was likely with the micro switch and I should contact the company so they could order the part. I duly did as asked, the thermostat did click so I passed on the information to the company.

A couple of days later, they contacted me to say that they wanted to send out an engineer to make sure they were ordering the correct part. I agreed to this and engineer 2 turned up. I was working, but my wife explained the problem to him, he looked at the system and suggested that the fault actually lay with the thermostat on the cylinder. My wife explained to him that the hot water was fine, but he insisted it was the cylinder thermostat and order a replacement.

Engineer 2 returned and replaced the thermostat, insisted the system was working because there was heat in the radiators (he had switched on both hot water and heating) and left. The next time we tried to switch on the heating, same fault.

Contacted the company again and they sent out Engineer 2. He looked again and decided that in fact, the whole mid position valve was faulty and needed replaced. The part was ordered and he eventually came round to fit it.
As mentioned above, the original valve was a Honeywell V4073A motorised mid position valve. The new valve is a Dayton ZA3 diverted valve. He drained down the system, replaced the valve, but then couldn't get the system to refill, blaming an air lock and blocked cold feed pipe. He said he didn't have the tools to unblock the feed pipe, so decided to backfill the system. After 3 failed attempts, he got the system back filled and left. We switched on the heating and nothing happened. We switched on the hot water and the radiators heated up to unbearably high temperatures but we had no hot water at all.

Called them back out, engineer 2 returned, drained the system, took the valve out, put it back in, messed about in the loft and then decided that the programmer was faulty. Said he'd order a new one and left.

That night, I noticed water coming through my living room ceiling. I drained the system, switched off the mains water and called them back out, only to be told there were no emergency engineers and I would need to phone again in the morning. Eventually, Engineer 3 arrived at 6pm the next night after I'd taken the day off work. He fixed the leak (Engineer 2 had left the safety valve on the pump open) and refilled the system. He then proceeded to get two electric shocks from the copper pipes. He took a quick look at the wire centre and reckoned it hadn't been wired correctly - the only change recently being the new valve. By this point it was 7:15pm and he couldn't stay any later (the poor guy had travelled quite a distance and mentioned he'd spent his whole day fixing engineer 2's mistakes). He recommended calling the company in the morning but that he system should remain off until it was checked.

I called the company back the next morning and they told me that the electric problem was a fault with my house and that I needed an electrician. I explained that their engineer had suggested that the wire centre was incorrectly wired and they agreed to send someone else out.

Engineer 2 was meant to come this morning but didn't show up, so after another irate phone call, they've agreed to send engineer 3 out on Wednesday.

Anyway, I have had a look around the forums and I have discovered that the Honeywell valve which was removed was a 5 wire mid position valve and the new valve is a 3 wire diverter valve. I think this might be the reason that the system isn't working properly, but I don't have a lot of knowledge in this area. If it is the case that the new actuator is the problem, would the whole valve need replaced, or could a Honeywell motor just be swapped in in place of the Dayton unit?

Any advise would be great fully received!

 

[D_Hailsham]

the original valve was a Honeywell V4073A motorised mid position valve. The new valve is a Dayton ZA3 diverted valve.

I have discovered that the Honeywell valve which was removed was a 5 wire mid position valve and the new valve is a 3 wire diverter valve.

They have installed the wrong valve.

Fortunately it's just a case of changing the actuator (control box) from a ZA3 to an MA1; and wiring it correctly!

What is a healthcare company doing providing heating service contracts? I would give them the boot - once they have put right their mistake.

 

[Frustratedhouseowner]

That was a Freudian slip! I work in healthcare, but I'm sure I meant heat care

Thanks for the advice, I shall chin them when (if) they turn up on Wednesday and then tell them they can cancel my contract - once they've paid to paint my ceiling!

 

[dcawkwell]

It a sad fact that this was an easy problem to fix.
Even if an engineer decided to replace hot water tank stat, 3 port valve and wall thermostat it would have been quicker than this fiasco and most likely
cheaper. That's assuming they could actually wire it up.
The problem was most likely the 3 port valve or simply the wall thermostat.

But pay peanuts and you get monkeys.
Get a local guy in who knows what he is doing.

 

[Frustratedhouseowner]

Well they've been back out and had another look.
The engineer that came out agreed that the incorrect actuator has been put on and is going to order the correct one. He also said the wiring was a bit of a mess and he'll redo that when he gets the new part.

However, when he tested the room stat, it's only getting 20volts through it when the heating is switched on at the programmer. He reckons that the programmer has been at fault the whole time. Does that sound reasonable?

He also said that the voltage through the pipes (measured between 3-4volts) isn't coming from the wiring box as it's a contained unit. I'm still a bit dubious about that though as the wiring centre is clearly incorrectly wired but he said there must be a live wire touching the pipes elsewhere.

I'm still only getting heating when I turn on the hot water on the boiler, although the immerser works. Does it sound like they're finally on the right track?

 

[D_Hailsham]

The engineer that came out agreed that the incorrect actuator has been put on and is going to order the correct one. He also said the wiring was a bit of a mess and he'll redo that when he gets the new part.

That's good news.

However, when he tested the room stat, it's only getting 20volts through it when the heating is switched on at the programmer. He reckons that the programmer has been at fault the whole time.

Did he disconnect the stat from the programmer and measure the voltage at the programmer CH On terminal? The 20V could be due to incorrect wiring and using the wrong actuator

he said there must be a live wire touching the pipes elsewhere.

If a wire was touching the pipe you would be getting 240V on the pipe and the fuse would blow! How old is the engineer?

I'm still only getting heating when I turn on the hot water on the boiler, although the immersion works. Does it sound like they're finally on the right track?

You will have that problem until the actuator is replaced and they are on the right track.

Just for your info, here is the "standard" wiring diagram for your system.

Click to enlarge, right click to save
View media item 31288

 

[Frustratedhouseowner]

However, when he tested the room stat, it's only getting 20volts through it when the heating is switched on at the programmer. He reckons that the programmer has been at fault the whole time.

Did he disconnect the stat from the programmer and measure the voltage at the programmer CH On terminal? The 20V could be due to incorrect wiring and using the wrong actuator

He couldn't get the programmer to come off of the wall. He said he didn't want to force it in case it broke.

he said there must be a live wire touching the pipes elsewhere.

If a wire was touching the pipe you would be getting 240V on the pipe and the fuse would blow! How old is the engineer?

This guy is probably in his mid - late 20's. He's certainly the youngest of the 3 but seems to actually have a bit of an idea as to what he's doing.

I'm still only getting heating when I turn on the hot water on the boiler, although the immersion works. Does it sound like they're finally on the right track?

You will have that problem until the actuator is replaced and they are on the right track.

Just for your info, here is the "standard" wiring diagram for your system.

Click to enlarge, right click to save
View media item 31288

Thanks for the diagram. It's of great help as I can actually get my head around it all. It looks like we have some old wiring in the house (odd given its only 20 years old) as we seem to have red, blue and green wiring. Presumably the red is the live in this case!

 

[diverdee]

there is no mid position valve with 3 wires its 4 or5

 

[ianmcd]

normally red is live blue is neutral and green is earth but this is very often not the case in heating system wiring, dont go by the colour of the wires alone in a heating system

 

[Frustratedhouseowner]

I'm afraid this is still continuing and I'm after some advice if anyone can help!
The company were scheduled to attend my property today to replace the Programmer, Mid Position Valve (to replace the Diverter valve) and to rewire the junction box. They were booked in for a full day job.
To cut a long story short, they didn't show up and when phoned they said they couldn't get someone out until the afternoon as it was only a small job.

I explained to them that it was quite a big job, but they said that they were only prepared to change the programmer as they have already replaced the valve.
I explained that their engineer had admitted that the incorrect part was fitted but they claimed that the reason it isn't working is because of the programmer. Whilst the programmer is faulty, the valve fitted is incorrect as detailed in the previous posts on this forum.
When I argued with them, I was told I couldn't take one engineer's word as gospel and that they would only change the programmer and if that didn't work they'd re-evaluate the fault and I could complain to the manager if I wasn't happy after that. I've now taken 12 days off work this year to deal with this and still haven't had a resolution.
I'm at the end of my tether with this as it's been ongoing for 3 months now.

Can anyone advise if I should follow what I've been told and wait for the programmer to be replaced, or should I cut my losses and try and get someone else in? I'm concerned that the cost to replace these components, rewire the junction centre and the labour will be quite high and clearly I'll have little chance of receiving compensation from the current company.

Thanks in advance for any assistance!

 

[Agile]

Its not difficult to realise that if you are paying peanuts then you are not likely to get very good service.

These firms can only afford to employ people who otherwise would find it hard to get a job. They are usually either newly qualified or those who have been doing it for years and still don't understand it.

Diagnosing faults is the key to success but these guys you see are just not up to it.

You have paid your money and can only wait until they have sorted it out unless you want to pay an independent.

Then you can complain if you have kept an accurate log. As far as compensation is concerned don't expect to get much more than an annual fee!

Tony