Central heating Query ( Honeywell & Baxi )

[chrisfoster1971]

Evening

Just wanted to run something past you and see what suggestions I get back as I am getting to the end of my knowledge but want to check my sanity before spending big bucks getting a local plumber in to sort it out.

1. Baxi Solo 3 PFL50 Boiler went faulty, replaced fan assembly and PCB ( however it has come to light the PCB wasn't actually faulty so now have a spare. Boiler starts working fine for approx two weeks

2. Hot water controlled via a Honeywell 699t controller and honeywell tank stat, room stat is a 6360b, with Honeywell v4073a 3 port valve.

problem I am having is only when the tank stat kicks in does the boiler fire up, not when the central heating is called for.

i've checked the stat is wired up and operating checking for power across terminals 1 and 2 on the thermostat, if it reads 240v then the programmer is fine (which it does ). Check for power across terminals 2 and 3, if it also reads 240v then the thermostat is also fine. You will then need to check the motorised valve.

I have done this and the motorised valve appears to work as when I up the tank stat up to max you can see the lever move all be it very slowly.

However during the water heating cycle the radiators do get hot ...

I am now not sure if to simply swap the valve head or replace the stat

Any ideas greatly appreciated.

 

[holty]

think you have answered your own question as to the cause. personally i would change the whole 3 port.not just the head, but if an old system and not looked after properly e.g sludge.be prepared.

 

[chrisfoster1971]

Holty, thanks for your quick response much appreciated.

The house was brand new 5 years ago and has run fine till a couple of weeks ago.

Luckily I found a reconditioning place adilink from Wembley were I got the boiler spares from but this has me baffled and with me having two small children the cooler nights are sometimes too chilly for them.

So next question is in that case.... what is involed to replace the crappy mechanical room start to a programmable unit ?

Plus does anyone have any good sources for parts as currently ebay is looking the best, but I prefer parts quicker

Also apart from Fernox what is the best conditioner to use as this hasn't been done whilst we have been in the house.?

Cheers..

 

[David937]

Also apart from Fernox what is the best conditioner to use as this hasn't been done whilst we have been in the house.?

Sentinel X100 inhibitor is your best bet.

 

[mlcinfl]

The house was brand new 5 years ago and has run fine till a couple of weeks ago.

Luckily I found a reconditioning place adilink from Wembley were I got the boiler spares from but this has me baffled and with me having two small children the cooler nights are sometimes too chilly for them.

So next question is in that case.... what is involed to replace the crappy mechanical room start to a programmable unit ?

Plus does anyone have any good sources for parts as currently ebay is looking the best, but I prefer parts quicker.

Commissioning of a central heating system is one of the most important aspects of the installation. Sadly, due to the time factor, most "new builds" are rarely commissioned thoroughly. Commissioning takes around 1/2 day. If you find that the system water is discoloured when you change the 3-way valve I would suggest that you de-scale the system with Sentinal 400 prior to treating with Sentinal 100. This can prevent circulation problems for many years ahead.

The Honeywell 6360B is not a "crappy" room stat. It may not be programmable, but is is reliable and will do what is required i.e. control room temperature.

I personally would avoid the Ebay route for any heating spares. Check out your local plumbing stockists and ask for prices. If you use Plumb Center or Screwfix for example, your product will be backed by a full warranty that you will be pushed to find on Ebay. You may pay a little more, but if it's minus 3c and your new 3-way valve fails you'll wish you'd paid the extra £20 and purchased locally.





Cheers..[/quote]

 

[chrisfoster1971]

The Honeywell 6360B is not a "crappy" room stat. It may not be programmable, but is is reliable and will do what is required i.e. control room temperature.

I personally would avoid the Ebay route for any heating spares. Check out your local plumbing stockists and ask for prices. If you use Plumb Center or Screwfix for example, your product will be backed by a full warranty that you will be pushed to find on Ebay. You may pay a little more, but if it's minus 3c and your new 3-way valve fails you'll wish you'd paid the extra £20 and purchased locally.

Well unfortunately I read this after comitting to a brand new in box 3 way valve off ebay for £21 instead of the £60 I was being quoted for just the power head and £125 from Plumb center for the whole unit

thanks for the Sentinel tip i shall get some of that and do a flush as like i say it has run for 5 years until now so I expect it needs a bit of TLC.

I have decided to change the stat for a Honeywell CM907 as I've never liked the stat being so basic and fancied being able to have different temps at different times on different days. Just need to suss out the difference between the 3 wire current installation and the 2 wire I believe this unit uses.

Thanks again for your help..

 

[gas4you]

What was the result of fitting the new 3 way valve head?

Your fault is a classic microswitch gone in the head, or incorrect wiring.

The tank stat provides the power for the boiler & pump when HW asked for, the valve head provides the power for the ch when asked for.

 

[chrisfoster1971]

Cheers for the reply


When we finally stripped the head down it does look like the microswitch had gone as you mention.

Get the new head today for £21 off ebay, local guy who's in the trade. So saved myself best part of £100 than buying it from Plumb Center

Thanks