Discuss having a dispute with another installer in the USA area at PlumbersForums.net
Not all boilers have flow switches, Worcesters don't they rely on differential between flow and return, a valve is still a valve with or without handleOverheat / flow switch if your that bothered remove the handles
Not all boilers have flow switches, Worcesters don't they rely on differential between flow and return, a valve is still a valve with or without handle
no because the filter only blocks one of the pipes to the exspansion pipe the other is still left open, and I have seen some really stupid tenants!Overheat
So that means every heat only boiler with a filter and external pump is at fault / problem
Remove the handles then you require tools to turn off and you should know better
no because the filter only blocks one of the pipes to the exspansion pipe the other is still left open, and I have seen some really stupid tenants!
Feed/expansion pipe/tank? Having looked at the layout of these (not really looked since college days 17 years ago ), I’m possibly understanding the problem.If the valves are shut and the boiler is fired up where does the expansion go?
Feed/expansion pipe/tank? Having looked at the layout of these (not really looked since college days 17 years ago ), I’m possibly understanding the problem.
Sealed systems have a safety valve for that very reason over exspansion in boilerAnd if sealed system and prv after pump like it normally is
Sealed systems have a safety valve for that very reason over exspansion in boiler
This is from some very old FAS (Irish) training course "Trade of Plumbing" but mentions a BS standard.
Open Vent Pipes and Safety Valves
The open vent pipe of non-ferrous material and minimum diameter of 22mm should be sited
so that it can discharge into the F&E cistern above the overflow level. The pipe should rise
continuously and avoid any horizontal runs. Any heated water which may be discharged from
the boiler must have a clear unobstructed path via the open vent pipe to the F&E cistern.
No valves or components, other than full bore pipe fittings, must therefore be fitted at a point
between the boiler and the discharge point of the system.
In addition to the open vent pipe, a safety valve should be fitted on the boiler or on the flow
pipe as near to the boiler as practicable. The location should enable visual indication if the
valve has lifted, but should not be in a position that could be a hazard to any person or
electrical
components in the event of discharging. Safety valves should conform toB.S. 759
In our previous diagrams we have shown the ideal locations for the cold feed and open vent,
in practice however you may find that they are actually part of the pipework circuit from the
boiler, show in the diagram below.
If you are referring to the safety valves, I agree, and it may have been the law back in those days even in England. This is clearly a modern boiler, however. Surely you aren't suggesting that virtually all modern RGIs (even Shaun!) don't know the rules? I suspect no-one is fitting PRVs or other safety valves as a supplement to open vents because boilers now have built in safety features that can deal with no-flow situations quite effectively (even an 8kW Thorn Apollo from the 1980s will shut down in seconds if an airlock develops in the flow pipe), and because (I assume) the current rules have been relaxed to take this into account.The quote in post#15 puts it well IMO as it states, "should be fitted".
Is that correct, or just the rubbish you end up coming across? I'd be more inclined to want the PRV to be upstream of the EV and thus between the pump and the boiler, though I'm ready to be told I'm wrong.And if sealed system and prv after pump like it normally is
I think 'should be fitted' means 'and jolly well shall be fitted', though, being course material, it isn't 100% clear what was a legal requirement and what was just the author trying to influence his students. I note the only 'must's in that entire extract refer to the same thing: not blocking the path between the boiler and the open vent i.e. ON THE FLOW (even though the wording is clumsy and you need to take the two 'musts' together for it to be clear that this is what it means), so I think your interpretation that 'must' refers to a legal requirement is probably correct.Don't think It was a legal requirement back then either as it would have stated "must be fitted"
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