I have another problem. I moved an outside tap for someone and after I shut the mains stopcock off and opened the existing outside tap and eventually hot water came out though it wasn't under much pressure and didn't last for long.
I notice there is no double check valve on the cold water feed to the boiler, the manufacturer's instructions show that this should be installed. So am I correct in assuming that when the mains water is shut down then we are draining off the central heating system from the outside tap, albeit the system in a vaccuum so it won't drain at speed????
Does the brass fitting at the end of the cold feed to the boiler (ie- that goes into the boiler) incorporate a check valve?
As the original installer didn't put in a dcv how bad is this?
Also when the outside tap is being used you cannot fill the boiler and also the shower doesn't work. The property has quite low pressure water but is there any kind of equalising valve that should be installed and where should it be installed?
When I arrived at the property they also said that the loft radiators weren 't working. I bled the radiators for a few minutes (!!!!) and everything ok. The loft radiators were installed in the summer and they said they had no trouble with cold rads last winter (before the loft conversion). Am I correct in saying that with the extra height that the loft radiators have, it has overcome the vacuum to send just the water from those loft rads through the outside tap as it has no dcv????
Hope this makes sense and thankyou for the help
I am currently doing a gas course at MET-UK so am still at a learning stage. I am looking for a placement (free!) from 30/11/09 in Derbyshire or Nottinghamshire.
> I have another problem. I moved an outside tap for someone and after I > shut the mains stopcock off and opened the existing outside tap and > eventually hot water came out though it wasn't under much pressure and > didn't last for long.
Could the cold water pipe that you drained run alongside a pipe holding hot water (CH or DHW)?
The cold water feed to the sink in one of our toilets runs alongside a central heating pipe for a short distance and so the cold water in the toilet sink runs warm for a brief period if the central heating has been running.
> > I have another problem. I moved an outside tap for someone and after I > > shut the mains stopcock off and opened the existing outside tap and > > eventually hot water came out though it wasn't under much pressure and > > didn't last for long.
> Could the cold water pipe that you drained run alongside a pipe holding > hot water (CH or DHW)?
> The cold water feed to the sink in one of our toilets runs alongside a > central heating pipe for a short distance and so the cold water in the > toilet sink runs warm for a brief period if the central heating has been > running.
> -- > F
Thanks I'll keep that in mind as a possibility but I doubt it as this would only be a possibility if the it was the pipes near to the boiler (as the pipe to outside tap is near boiler) and I can't see any pipes that would be causing this problem. Thanks again, Jon
> I have another problem. I moved an outside tap for someone and after I > shut the mains stopcock off and opened the existing outside tap and > eventually hot water came out though it wasn't under much pressure and > didn't last for long.
> I notice there is no double check valve on the cold water feed to the > boiler, the manufacturer's instructions show that this should be > installed. So am I correct in assuming that when the mains water is > shut down then we are draining off the central heating system from the > outside tap, albeit the system in a vaccuum so it won't drain at > speed???? No.
> Does the brass fitting at the end of the cold feed to the boiler (ie- > that goes into the boiler) incorporate a check valve? Probably not.
> As the original installer didn't put in a dcv how bad is this?
Not serious at all.
> Also when the outside tap is being used you cannot fill the boiler and > also the shower doesn't work. The property has quite low pressure > water but is there any kind of equalising valve that should be > installed and where should it be installed?
There is nothing to equalise. Just have to use only one tap/apliance at a time, don't flush toilet when showering.
> When I arrived at the property they also said that the loft radiators > weren 't working. I bled the radiators for a few minutes (!!!!) and > everything ok. The loft radiators were installed in the summer and > they said they had no trouble with cold rads last winter (before the > loft conversion). Am I correct in saying that with the extra height > that the loft radiators have, it has overcome the vacuum to send just > the water from those loft rads through the outside tap as it has no > dcv????
This bit does not make sense. Rads have nothing to do with domestic hot water flow.
> Hope this makes sense and thankyou for the help
> I am currently doing a gas course at MET-UK so am still at a learning > stage. I am looking for a placement (free!) from 30/11/09 in > Derbyshire or Nottinghamshire.
On Sun, 8 Nov 2009 03:22:47 -0800 (PST), jayseeblue wrote: > I have another problem. I moved an outside tap for someone and after I > shut the mains stopcock off and opened the existing outside tap and > eventually hot water came out though it wasn't under much pressure and > didn't last for long.
What sort of bolier system? Open vented, sealed/pressurised, combi?
I'm sort of thinking combi but your descriptions are not 100% consistent with that or any other system come to that...
> The property has quite low pressure water ...
There is a statutary minimum for water pressure, I forget what they are but have a dig about on the Ofwat website.
Yes it appears my arse and elbow were mixed up about the vacuum with the system being pressurised! Sorry I have got mixed up with when you bung the vent and feed on an traditional system to effect a vaccuum.
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