Cycling boiler problem

[lburton]

Hi I have a Ravenheat LS80 that was inherited with the house I bought, we've had it 4 years now with some issues through that time but nothing we haven't been able to sort out. The CH has now decided to start cycling and the hot water is no longer hot maybe only warm at a push, I really cant afford another boiler just yet and the engineers wont give much away either so I would be grateful for any advice you may be able to offer.

I called Ravenheat who told me something about some pressure switch in the pcb needing increasing but I need a bit more information to go on.

Many thanks

 

[Agile]

It could be several causes but more likely to be gas related which will require a gas registered engineer.

We dont give DIY gas advice on open forums.

The first test I would do would be to check the combustion settings.

Which engineers wont give much away? No engineer should be giving DIY gas advice!

Tony

 

[DP]

Lack of hot water may just be a seasonal thing as cold water is from the mains is a lot colder at this time of the year. However, other checks like what is the flowrate from the the hot tap, if gas settings are correct etc would help locate the defect if a defect does exist.

WRT boiler cycling, burner flame size varies as primary water temperature approaches the setting have selected on the facia controls.

Regret, area within the boiler case is a no go area for the end user as you will need tools and test gear to check or set up the boiler to data badge settings.

 

[lburton]

It could be several causes but more likely to be gas related which will require a gas registered engineer.

We dont give DIY gas advice on open forums.

The first test I would do would be to check the combustion settings.

Which engineers wont give much away? No engineer should be giving DIY gas advice!

Tony

Thanks for the reply Tony, it seems more like some overheating device which cuts out the heating and then the boiler immediately ignites, surely this shouldn't happen. Why do you think it could be a gas related problem out of interest?

All the parts I've had to deal with (or the 'engineers' who fit them) are the likes of pumps, diaphrams, timeclocks and gate valves thus far and I guess the reason they dont give much away is because they have looked and cannot confirm why it happens.

Point noted about the competent persons, if it is Gas related I would only want qualified people working on it as I'm sure the wif and family wouldn't be too pleased about that!

 

[lburton]

Lack of hot water may just be a seasonal thing as cold water is from the mains is a lot colder at this time of the year. However, other checks like what is the flowrate from the the hot tap, if gas settings are correct etc would help locate the defect if a defect does exist.

WRT boiler cycling, burner flame size varies as primary water temperature approaches the setting have selected on the facia controls.

Regret, area within the boiler case is a no go area for the end user as you will need tools and test gear to check or set up the boiler to data badge settings.

Hi DP, thanks for the reply, it may be a seasonal thing but surely this cant be right? The flow rate is very good, maybe even too good. When I turn the bath or shower tap down the water heats up although that doesn't cure the cycling whatever the internal thermostat is set at. I have rad stats up stairs but removed them downstairs as they are behind covers and we dont seem to get any heat out of them, do you think this may be a cause?

 

[DP]

The flow rate is very good

That is what is wrong. Flow rate CANNOT be got- it can only be 9.5l per minute for 35 degree temperature rise. During hot water delivery, burner should not go out even when at full setting and tap at full flow (delivering 9.5l per minute)

Pity you do not have earlier model that had a temperature guage- that would have helped with remote faulting

 

[lburton]

The flow rate is very good

That is what is wrong. Flow rate CANNOT be got- it can only be 9.5l per minute for 35 degree temperature rise. During hot water delivery, burner should not go out even when at full setting and tap at full flow (delivering 9.5l per minute)

Pity you do not have earlier model that had a temperature guage- that would have helped with remote faulting

Sorry I'm maybe confusing things as I'm talking about two different issues:

1. the hot water is not that hot - the burner never goes out for this, taps seem to have a good flow rate whatever that is (suggestions how I can meausre this), but if I turn them down a tad the water heats up?
2. the CH cycles no matter what it is set to on the boiler (unless I demand HW), the CH will go until it reaches its temperature then just constantly cycle rather than sustained periods of cooling down and warming up.

Thanks

 

[Agile]

You seem to be describing the same symptoms on both CH and DHW. Thats why I suspect its gas related.

The first thing any engineer is likely to do is to check the gas setttings and consumption.

Tony

 

[DP]

Run tap at full flow, collect water for timed 15 seconds in a bucket and measure what you have collected. Times 4 gives you hot water flowrate.

Second pipe in from left is the pipe that delivers heated water to the radiators. Either take temperature readings or 'feel' how hot this pipe is. Then go to a radiator and determine if the inlet pipe is the same temperature. Try other radiators.

I think you need your boiler serviced. Problem would seem to be internal to the boiler.