Hi. Looking for some advice with a few issues.
I have an oil fired heating system and an unvented Santon Premier Plus mains pressure water heater. Specs as below.
Maximum water supply pressure to PRV 16.0 bar
Operating pressure of unit 3.5 bar
Expansion vessel charge pressure 3.5 bar
Expansion valve setting 6.0 bar
Nominal storage capacity of units (see Section 2 Table 2)
Max. primary working pressure 3.0 bar (indirects only)
Opening temperature of T&P Relief Valve 90deg C
Opening pressure of T&P Relief Valve 10 bar
I have had a drip from the tundish for quite some time. A few months back I also tested the white 18ltr potable expansion tank and there were signs of liquid coming out the Schraeder Valve. So I purchased a new tank. It was pre charged to 2 bar, although my Santon tank specifications recommend charging to 3.5 bar. I fitted it with no issues, but after a while, there was a loud drone for about 5 seconds on turning on a hot water tap or shower, particularly in the ensuite which backs on to the airing cupboard.
So first I increased the pressure in the expansion valve to about 3.5bar, , but the drone was still there. I then decreased it gradually to about 2.4bar until the drone went away.
I left all the pipework exposed for a few days (with all clothes and shelves removed from the airing cupboard for access).
My findings since have me a bit puzzled.
I have a pressure gauge screwed on temporarily to a check point on the Cold Water Combination Valve (CWCV) (see photo 1 attached) and another tyre pressure gauge I can place on the Schraeder valve on the Expansion tank.
I will also say, A few years ago I had an engineer look at the system and he said the mains pressure at the water tank was too high, I think he fitted a restrictor of some sort to reduce the mains pressure at that time.
So... over the last few days, most of the time, the pressure gauge connected to the CWCV shows 3.1bar (presumably that's the inlet mains pressure?), and the pressure from the expansion tank shows approx 3 bar that with it under normal operation pressure.
However. Last night after the oil fired boiler completed its 1 hr water heating cycle at 6pm, I checked the system, and the gauge at the the expansion tank maxed out at 4.1bar (as high as the gauge goes, so actual pressure could be higher).
An hour ago I ran the hot water on the shower , and monitored the gauges.
At the CWCV the pressure with the shower running had dropped to 1 bar,(see photo 1). the gauge at the exp tank about 1 bar also. Immediately on turning the shower off, the gauge at the Combi valve showed 3.1bar, and the expansion tank the same.
However, 30 mins ago I checked both again, and the both gauges are creeping back up again, the one at the CWCV shows 4bar currently, and approaching 4 bar on the expansion tank.
There is currently no leaks at the tundish, but it seems to come and go, and usually warm though not scalding water.
Firstly what would be regarded as the correct pressure from the cold inlet pipe coming into the airing cupboard? I presume the 3 bar I am measuring at the CWCV is 3 bar for me?
Secondly, what pressure should the Expansion tank be shown when under normal load, ie not drained. Mine was set from new at 3.5 bar before connecting up, but I had to reduce that to 2.4bar due to the droning. Its about 3 bar when under normal pressure rising on its own to over 4 bar when the heating boiler is on at the timer.
Thirdly, is it normal for the pressure to creep up like Ive explained after turning a hot tap or shower off? Would 4.5 bar at the CWCV and +4bar on the fully pressurised expansion tank be acceptable?
I need to watch for a pattern with the drip at the tundish, at the moment there is no drip, but there has been under certain circumstances.
I know the TPRV or PRV could be faulty or both, but I am confused because of the drops and increases in pressures recorded and whether this is within acceptable parameters. I have also posted some extra pictures showing my setup with the various valves.
I would appreciate some advice. I will call in an engineer if the PRV or TPRV valves need replaced but I would like to know the possible issues here first.
Many thanks
I have an oil fired heating system and an unvented Santon Premier Plus mains pressure water heater. Specs as below.
Maximum water supply pressure to PRV 16.0 bar
Operating pressure of unit 3.5 bar
Expansion vessel charge pressure 3.5 bar
Expansion valve setting 6.0 bar
Nominal storage capacity of units (see Section 2 Table 2)
Max. primary working pressure 3.0 bar (indirects only)
Opening temperature of T&P Relief Valve 90deg C
Opening pressure of T&P Relief Valve 10 bar
I have had a drip from the tundish for quite some time. A few months back I also tested the white 18ltr potable expansion tank and there were signs of liquid coming out the Schraeder Valve. So I purchased a new tank. It was pre charged to 2 bar, although my Santon tank specifications recommend charging to 3.5 bar. I fitted it with no issues, but after a while, there was a loud drone for about 5 seconds on turning on a hot water tap or shower, particularly in the ensuite which backs on to the airing cupboard.
So first I increased the pressure in the expansion valve to about 3.5bar, , but the drone was still there. I then decreased it gradually to about 2.4bar until the drone went away.
I left all the pipework exposed for a few days (with all clothes and shelves removed from the airing cupboard for access).
My findings since have me a bit puzzled.
I have a pressure gauge screwed on temporarily to a check point on the Cold Water Combination Valve (CWCV) (see photo 1 attached) and another tyre pressure gauge I can place on the Schraeder valve on the Expansion tank.
I will also say, A few years ago I had an engineer look at the system and he said the mains pressure at the water tank was too high, I think he fitted a restrictor of some sort to reduce the mains pressure at that time.
So... over the last few days, most of the time, the pressure gauge connected to the CWCV shows 3.1bar (presumably that's the inlet mains pressure?), and the pressure from the expansion tank shows approx 3 bar that with it under normal operation pressure.
However. Last night after the oil fired boiler completed its 1 hr water heating cycle at 6pm, I checked the system, and the gauge at the the expansion tank maxed out at 4.1bar (as high as the gauge goes, so actual pressure could be higher).
An hour ago I ran the hot water on the shower , and monitored the gauges.
At the CWCV the pressure with the shower running had dropped to 1 bar,(see photo 1). the gauge at the exp tank about 1 bar also. Immediately on turning the shower off, the gauge at the Combi valve showed 3.1bar, and the expansion tank the same.
However, 30 mins ago I checked both again, and the both gauges are creeping back up again, the one at the CWCV shows 4bar currently, and approaching 4 bar on the expansion tank.
There is currently no leaks at the tundish, but it seems to come and go, and usually warm though not scalding water.
Firstly what would be regarded as the correct pressure from the cold inlet pipe coming into the airing cupboard? I presume the 3 bar I am measuring at the CWCV is 3 bar for me?
Secondly, what pressure should the Expansion tank be shown when under normal load, ie not drained. Mine was set from new at 3.5 bar before connecting up, but I had to reduce that to 2.4bar due to the droning. Its about 3 bar when under normal pressure rising on its own to over 4 bar when the heating boiler is on at the timer.
Thirdly, is it normal for the pressure to creep up like Ive explained after turning a hot tap or shower off? Would 4.5 bar at the CWCV and +4bar on the fully pressurised expansion tank be acceptable?
I need to watch for a pattern with the drip at the tundish, at the moment there is no drip, but there has been under certain circumstances.
I know the TPRV or PRV could be faulty or both, but I am confused because of the drops and increases in pressures recorded and whether this is within acceptable parameters. I have also posted some extra pictures showing my setup with the various valves.
I would appreciate some advice. I will call in an engineer if the PRV or TPRV valves need replaced but I would like to know the possible issues here first.
Many thanks
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