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Post by lollygagger on Apr 21, 2017 11:35:03 GMT
I did a silly thing a while back. While fixing leaks I took the pump apart a bit. By the time I realised one of the screws was for adjusting it I'd lost track of where it was set, so I turned it down then gradually up until the pump kicked in just as the water was almost stopping. Having shifted my attention to pressure temporarily it seemed higher than I remembered which is why I set it low. I don't really understand the pressure setting but another thing that's happened since I messed about is the cylinder venting into the engine bilge via a pressure relief valve which would point to the pressure being higher than it was before I fiddled. I'm confused because the pump adjustment seems to adjust the low point where the pump kicks in rather than the system pressure, so how could the max pressure have risen? I have acquired a pressure gauge to fit in the cold feed which I'll fit shortly but then what? Any pointers gratefully received.  |
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Post by lollygagger on Apr 21, 2017 14:49:34 GMT
I've fitted the gauge and have 32psi - 2.2bar. Sadly it on a NRV so max only unless I crack a joint and let the pressure out.
From googling the pump cut out pressure can be adjusted, but not the cut in pressure. I think if I turned up the pressure, it might cut in sooner too.
Would anyone know how high I can typically set pressure on a narrowboat system? I have a mix of copper, flexible hoses and push fit plastic plumbing.
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Post by tonyb on Apr 21, 2017 15:09:11 GMT
The higher you go the more chance of leaks but the limiting factor is the setting of the Pressure relief valve that is normally around the calorifier. If you have say a 2 bar PRV (30psi) I would set the pressure to no more than 25 psi to allow for possible pressure pulses as you turn the taps off, 20 psi may be needed in bad cases.
Do not fit a higher PRV unless the calorifier supplier OKs it.
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Post by Deleted on Apr 21, 2017 15:21:45 GMT
Here's what we have:-
Shurflo trailking 7, 20 psi cut out, 10 psi cut in.
2.5 bar PRV (36 and a knacker psi) cauliflower pressure tested to 3bar by me. Expansion vessel set to 36psi
Accumulator set to 7psi
No lifting of PRV, no leaks, good pressure and flow.
👍
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Post by lollygagger on Apr 21, 2017 16:15:26 GMT
To set it, I screwed the screw carefully until pump cut in so I can see it's my setting that makes it wait until virtually stopped before kicking in. If I have a shower, I get an accumulator's worth them nothing until I lower the shower head a foot.
I think I'll readjust the pump the same way as before then 1/2 a turn extra and see what happens. Maybe I inadvertantly set the pump to max pressure.
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Post by lollygagger on Apr 21, 2017 17:12:09 GMT
For the benifit of poor sods googling in 10 years time...
It's a shurflo 3901-0213 rated at 30psi. Hmmm...
I screwed the adjust one turn in 3.2bar, 48psi!
Trying the shower test I then managed to lower the pressure (unscrew) back down to 2.3bar which though barely higher than it was makes everything work properly.
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Post by lollygagger on Apr 21, 2017 17:20:16 GMT
...But I just realised my hot water expansion pressure relief is going to be filling the engine bay double quick with a new higher base pressure to start from. They look adjustable and I'm ready to believe probably set without a gauge...
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Post by lollygagger on Apr 21, 2017 17:27:43 GMT
I hate plumbing. Adjustable PRV.  On the end...  Righty ho. Something happens in the direction of the arrow and 2 bar comes into it. |
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Post by JohnV on Apr 21, 2017 19:18:05 GMT
I think you will find that is a set 2 bar and the arrow just points in the direction you turn it to manually open the valve be careful that it re-seats properly when released  I am however quite happy to be shown to be wrong !!! |
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Post by Deleted on Apr 21, 2017 19:18:44 GMT
It's not adjustable, it lifts at 2 bar.
Its Dependent on the test pressure of your cauliflower - you may have too high a pressure pump
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Post by lollygagger on Apr 21, 2017 19:29:09 GMT
It's not adjustable, it lifts at 2 bar. Its Dependent on the test pressure of your cauliflower - you may have too high a pressure pump It didn't vent before I inadvertantly fiddled yet the pressure must have been higher because the shower didn't stop. I need another accumulator in the hot pipe I reckon. |
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Post by Deleted on Apr 21, 2017 20:12:13 GMT
It's not adjustable, it lifts at 2 bar. Its Dependent on the test pressure of your cauliflower - you may have too high a pressure pump It didn't vent before I inadvertantly fiddled yet the pressure must have been higher because the shower didn't stop. I need another accumulator in the hot pipe I reckon. Accumulator in the cold supply from pump before NRV, expansion vessel in the hot out - odd diagram gives it as expansion vessel cauliflower cold inlet after the NVR, I haven't told my expansion tank it's in the hot out so it's happy in its ignorance |
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Post by JohnV on Apr 21, 2017 20:14:19 GMT
It didn't vent before I inadvertantly fiddled yet the pressure must have been higher because the shower didn't stop. I need another accumulator in the hot pipe I reckon. Accumulator in the cold supply from pump before NRV, expansion vessel in the hot out - odd diagram gives it as expansion vessel cauliflower cold inlet after the NVR, I haven't told my expansion tank it's in the hot out so it's happy in its ignorance Yup !!! mine is just as ignorant ....... and just as happy  |
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Post by lollygagger on Apr 21, 2017 20:18:38 GMT
It didn't vent before I inadvertantly fiddled yet the pressure must have been higher because the shower didn't stop. I need another accumulator in the hot pipe I reckon. Accumulator in the cold supply from pump before NRV, expansion vessel in the hot out - odd diagram gives it as expansion vessel cauliflower cold inlet after the NVR, I haven't told my expansion tank it's in the hot out so it's happy in its ignorance In the hot it fills with (and wastes) about half an accumulator of hot. In the hold it wouldn't. My NRV appears to be part of the calorifier so I'd have to put it in the hot which is annoying. |
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Post by Deleted on Apr 21, 2017 20:20:45 GMT
Accumulator in the cold supply from pump before NRV, expansion vessel in the hot out - odd diagram gives it as expansion vessel cauliflower cold inlet after the NVR, I haven't told my expansion tank it's in the hot out so it's happy in its ignorance Yup !!! mine is just as ignorant ....... and just as happy It's all about the packaging, I couldn't get everything wedged in one corner of our arse end - we would need a small plant room if you stuck to the surecal and shurflo diagrams! I can't get my head round why they think expansion only occurs in the cold inlet side either |
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