The prob being?
Nowadays auto by-pass valves are rarely required, perhaps only on a fully zoned system with a boiler requiring pump over-run.
BYPASS
- Thread starter SortedPlumbing
- Start date
The prob being?
Nowadays auto by-pass valves are rarely required, perhaps only on a fully zoned system with a boiler requiring pump over-run.
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The OPs problem was simply due to zero flow (or very reduced flow) as the TRVs shut down causing overheats and shutdown......this was entirely down to incorrect installation of the system.
The Ravenheat boiler does not incorporate a flowswitch assembly therfore a room stat must be installed (in the zone with the uncontrolled radiator) to provide the interlock and compliance.
However the boiler MIs specifiy a minimum flowrate which may not be met by the uncontrolled rad (if it's fairly small). Therefore it may still be necessary to fit an ABV...however with TRVs fitted to the rest of the rads it may be essential to prevent noise.
Ravenheat must be one of the few manufacturers that don't fit an ABV within the boiler (perhaps it's just this model). With the Giannoni heat exchanger serious damage is a possibility with a "no flow" scenario since the overheat stat/flow thermistor is located at some distance down the flow pipe from the unit. And with an O ring connection the pipe is some what insulated from the heat ex. What's even more worrying is the lack of a flue overheat sensor despite the use of plastic flue components. The water pressure switch (simple 2 wire on/off) of course wouldn't know if the heat exchanger was full of air or the pump had failed. I suspect diyers are going to have some very expensive repairs when they inadvertantly dry-fire their boilers after a drain down with the heat exchanger full of trapped air.
The Ravenheat boiler does not incorporate a flowswitch assembly therfore a room stat must be installed (in the zone with the uncontrolled radiator) to provide the interlock and compliance.
However the boiler MIs specifiy a minimum flowrate which may not be met by the uncontrolled rad (if it's fairly small). Therefore it may still be necessary to fit an ABV...however with TRVs fitted to the rest of the rads it may be essential to prevent noise.
Ravenheat must be one of the few manufacturers that don't fit an ABV within the boiler (perhaps it's just this model). With the Giannoni heat exchanger serious damage is a possibility with a "no flow" scenario since the overheat stat/flow thermistor is located at some distance down the flow pipe from the unit. And with an O ring connection the pipe is some what insulated from the heat ex. What's even more worrying is the lack of a flue overheat sensor despite the use of plastic flue components. The water pressure switch (simple 2 wire on/off) of course wouldn't know if the heat exchanger was full of air or the pump had failed. I suspect diyers are going to have some very expensive repairs when they inadvertantly dry-fire their boilers after a drain down with the heat exchanger full of trapped air.
dont bother beating yourselves up about it anymore.
Now that I am doing checks on council properties I realise we independents are tring our best to get it right and councils are flouting the regs. when you open airing cupboard doors its like geting off the plane in Jamaika.
The prgrammers are largely ignored by tenants leaving them on 24/7 boiler stats are set to max cyl stats set far too high pipes not lagged non complien cylinders despite a new boiler having been fitted 2006 is typical.
I aint going to police it no more for the gov, I'll tell the client the facts and then do what they want. No reason we the self employed should police it when nobody else is.
Now that I am doing checks on council properties I realise we independents are tring our best to get it right and councils are flouting the regs. when you open airing cupboard doors its like geting off the plane in Jamaika.
The prgrammers are largely ignored by tenants leaving them on 24/7 boiler stats are set to max cyl stats set far too high pipes not lagged non complien cylinders despite a new boiler having been fitted 2006 is typical.
I aint going to police it no more for the gov, I'll tell the client the facts and then do what they want. No reason we the self employed should police it when nobody else is.
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That is true.
That is true was not for baxpotty.
That I disagree with most systems require an auto by-pass.
Clear as mud then!
That is true.
That is true was not for baxpotty.
That I disagree with most systems require an auto by-pass.
Clear as mud then!
Was wasn't it
I replied to the post before yours.
So I edited it to make it clear I didn't agree with your post about not needing a by-pass valve
Carry on rssteve don't mind us dinasaurs
Em !!!! the question, yes, that is what room stats do.
thats the idea
For studios and small flats it's best to fit the stat in the living room...this will be the warmest area and provided the radiators are sized correctly the rest of the property will have reached set temperatures (and the TRVs shut down) before the room stat shuts off the boiler.
Larger properties normally have the stat in the hallway/landing. Radiators in these areas (fitted with lockshields each end) can always be throttled down so this area becomes the last to heat up.
Obviously it gets a little more complicated when solar gains are accounted for with large South facing windows and gas fires.
It's by no means perfect but is the least cost option to comply.
Larger properties normally have the stat in the hallway/landing. Radiators in these areas (fitted with lockshields each end) can always be throttled down so this area becomes the last to heat up.
Obviously it gets a little more complicated when solar gains are accounted for with large South facing windows and gas fires.
It's by no means perfect but is the least cost option to comply.
ok thanks for your answer, i don't think the others understood my question or were being sarcastic(sp)
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