Infrared thermometer giving duff readings!

[Chameleonclaude]

My other thought was whether the gas/air ratio is correct.

I had a neighbour install the boiler for me for £300. He's a fully qualified corgi plumber but can't imagine he would have had a worcester bosch manometer and done a full check.

Is this theory a case of 'A little knowledge is a dangerous thing'?

 

[D_Hailsham]

I'll do a more thorough test tonight but i know the bypass is allowing 4 litres per minute when CH motorised valve is open, and 5 litres per minute when closed. 5 lpm is the boilers stated requirement for over run.

You haven't said which boiler you are talking about.

If all rad valves are open there shouldn't be any flow through the bypass.

 

[Chameleonclaude]

My boiler is a worcester bosch 24ri (or may be an 18ri, can't remember!).

Bypass is open during operation because i have a modlating pump which doesn't work to well with auto bypass valves. Instead i fitted a taconova inline flow setter.

I'm considering routing the bypass through our bathroom towl rail as an 'always on'. The rational is it will aid in the cooling process during overun and it will create a little more back pressure which will reduce the flow through it during CH operation. Problem could be that it also reduces flow below 5 litres per minute during overun. Tricky!

I though about installing a three way motorised valve at the bypass/flow tee which would be wired to open when ch and hw are closed during overun but the motorised alves take longer to open than they do to close which would cause periods of no flow which could harm the boiler and the pump.

 

[Chameleonclaude]

Wat i don't get though, is that if my boilers fan quietens right down. Though it has reached temperature and is now reducing flame to maintain temperature, then surely this implies that it is at the designated temperature for that position on the temperature dial.

 

[D_Hailsham]

My boiler is a worcester bosch 24ri (or may be an 18ri, can't remember!).

Where does it say in the installation manual that the flow has to be 5 litres/min?

 

[Chameleonclaude]

I called the worcester bosch tecnical team who advised me.

It could be that that's there stock answer which is a overkill, but what to do!

 

[D_Hailsham]

Wat i don't get though, is that if my boilers fan quietens right down. Though it has reached temperature and is now reducing flame to maintain temperature, then surely this implies that it is at the designated temperature for that position on the temperature dial.

That all depends on which thermostat has turned the boiler off!

If the boiler comes back on when you turn the room stat up to a very high level, then the room stat has turned the boiler off. But if the boiler does not come back on, then boiler stat has turned the boiler off.

 

[Chameleonclaude]

When i say it quietens right down, i mean that the system hasn't turned off but the boiler is modulating. Have i missed the point?

 

[D_Hailsham]

When i say it quietens right down, i mean that the system hasn't turned off but the boiler is modulating. Have i missed the point?

No, but I misunderstood what you were saying.

The reason for the boiler modulating down may be due to the flow temperature reaching the required value, but it could be due to other factors, such as the return temperature or the temperature differential. Modern condensing boilers have more sophisticated control systems than just the simple flow thermostat of old boilers.

Did the installer rebalance the rads for a 20C differential?

 

[Chameleonclaude]

I'm not sure but will check tonight.

I think i must balance all my rads otherwise hotter water will return to the boiler before the colder rads have had the chance!

I shall balance all the rads and then see what happens. I did wonder whether the boilers modulating calcs are based on return temperature!

Thanks dude. I shall do some testing tonight and reply.

 

[D_Hailsham]

How to balance a CH system

 

[Chameleonclaude]

Thanks to all whom have given me there time and expertese on this thread.

Due to evolving subject matter i will raise a new thread about balancing and bypass's.

Would your support on that one.

 

[Chameleonclaude]

So this morning i had a worcester bosch registered installer come and check my boiler over due to the low flow temperatures. It transpires that my boiler is a 15ri which could be underpowered given the old stype 4 colmn rads i've installed and the large water volume of them.

After checking this and that, the upshot is that when he increased the gas air ratio above the 8% (the minimum recommended being 9.2 and the max being 9.8 ) the CO2 levels went through the roof (over 2000 ppm). He tinkered around, spoke to worcester bosch technical team and after £100 of service time the boiler is exactly as it was when he got here (dysfunctional)

Even when her increased the g/air ration to max. Regardless of ppm the boiler never heated the flow above 60 degrees.

Worcester bosch are washing their hands of it and advising me that my only solution is to pay three hundred pounds and get their service package which includes the cost of any parts.

How crap is that! I'm so upset about this

Anyway, there is no way i'm paying worcester £300 to repair a boiler of just 3 years of age. With summer on its way i shall suffer the cold days and save my pennies to buy a new more powerful boiler with weather compensator abilities.

Can anyone tell me the rolls royce of boilers? (clearly not worcester bosch)

 

[Dan Robinson]

What is the heat loss of you house? Large water volume is a good thing for Condensing boilers.

Even so - cranking up the CO2 will do diddly squat.

Does the boiler fire constantly during a demand for heat? OR does it cycle?

 

[Dan Robinson]

As for best boilers - you should be looking at Atmos or Intergas (in that order).