Water pump issues

[JonnoR]

Morning all,
Am away in my CV and have a bit of an issue. Upto now the Water pump had been working all ok, filled up yesterday with water and the from then on in the pump would randomly start up for 30s and then stop. We checked all taps none were on or leaking. Checked some visible pipes for leaks - none. So we turned the pump off overnight. This morning water level still at 50% however we have no water the pump is working but when any tap is turned on no water appears. Have checked the water pump for leaks, nothing.
Any thoughts on a remedy / cure
TIA.

 

[Phantom]

Check that the pipe has not come off the pump in the water tank.

 

[r4dent]

MoHo water system 101
Most water systems these days work on a pressurises system.
A water pressure sensor (can be separate or built into the pump) i the water pipe between the pump and the taps checks the pressure, if it is below the target pressure completes the 12v circuit which powers the pump.

So in normal use it works like this.

The system is pressurised, the pump is off.
You turn a tap on; water comes out of the system and the water pressure drops; the sensor completes the 12v circuit and the pump runs.

You close the tap and the pump continues running (for seconds); water cannot leave the system and so pressure builds up; the sensor detects the higher pressure and switches off power to the pump.

If you have a small leak (usually in a hidden and inaccessible location) water slowly escapes; the pressure falls, the sensor switches on power; the pump runs; more water is in the system; pressure increases and after a few seconds reaches the target; the sensor switches off power. After a few hours this is all repeated.


This sounds exactly like your initial situation. Most people find this annoying but can not find a leak and so circumvent the problem by turning the pump off at the control panel (just like you did).
ACTION 1 With the water pump switched on and all taps closed, have a better look round (including underneath) to try and find the leak.

A faulty sensor can cause a similar problem as can a small piece of grit which allows water to flow backwards out of the system and thus decreases the pressure.
ACTION 2 Find / remove / clean / degrit* / rinse / refit the sensor. (see video

).
*Most pressure sensors are adjustable using a circular disc on the top
To degrit the sensor
a) Mark the position of the adjustment disc
b) Twist the disc from one a extreme to the other several times. This can dislodge grit particals
c) Return the disc to the original setting.

ACTION 3 Model / year of MoHo & Make /model of pump may help us.



I'll comment of the lack of water later (breakfast ready).

Good Luck

 

[r4dent]

This morning water level still at 50% however we have no water the pump is working but when any tap is turned on no water appears.

I suspect that you have an "air lock". This is just a technical term meaning that air is trapped in the system and the water can't get in.

When you have drained the system after your previous trip the tank / boiler/ tank / pump / pipework / filter are not empty!
They are full of air.

A lot of people fill the tank with the taps closed, the air in the system cannot get out and is trapped in the system.

ACTION. Drain and refill the fresh water tank.

I always use this method and have never had an airlock

a) switch pump off
b) drain tank
c) open all taps (this gives the air a way out of the system)
d) Start filling tank

When the tank is half full (continue filling the tank)
e) Close all taps except sink cold
f) turn pump on
g) water should start to come out of tap
h) close sink cold
i) open each cold tap in turn, close when water comes out (this purges air from pipework)
j) open each hot tap in turn, close when water comes out (this primes the boiler)
k) continue until tank is full

 

[JonnoR]

Manufacturer has advised that more than likely the pump has gone, guessing the pump element as the motor still works. That will be the second pump in 2 yrs. Anyone had experience with Flojet pumps failing and if so are they repairable, thinking of getting a new one repairing the old and having it as a spare.

 

[colinm]

Have you checked the dump valve, just in case it's tripped.

 

[Bigshug]

The pump cycling on and off would make me think that when the pressure drops the pump fires up to repressurise the system..l would be looking for a leak after the pump, do you have a water heater? If so check that the dump valve is not leaking.

 

[JonnoR]

Have you checked the dump valve, just in case it's tripped.

Can you advise where the valve is,is it on the pump itself or close to the inlet or outlet

 

[colinm]

Can you advise where the valve is,is it on the pump itself or close to the inlet or outlet

If you have a Truma heater it will be close to that, have you looked underneath the van when the pump is running?
p.s. if no other leaks then as the manufacturer has advised, a failed pump is probably the culprit, but two in two years seems excessive.

 

[Canalsman]

I suspect an air lock as suggested previously.

 

[TJBi]

With limited information regarding the system, it's a bit difficult to comment, but certainly sounds as though it could be an airlock. It would be interesting to know on what data the manufacturer based the suggestion that the pump had failed. Two in two years does sound excessive, but friends who owned a Bürstner some years ago did have problems with submersible pumps failing frequently, to the extent that they took to carrying a complete spare unit.

 

[Canalsman]

With limited information regarding the system, it's a bit difficult to comment, but certainly sounds as though it could be an airlock. It would be interesting to know on what data the manufacturer based the suggestion that the pump had failed. Two in two years does sound excessive, but friends who owned a Bürstner some years ago did have problems with submersible pumps failing frequently, to the extent that they took to carrying a complete spare unit.

The diaphragm type of pump, which is what the Flojet is, should last almost indefinitely. The point of failure is the diaphragm itself which is easy to replace.

My Shurflo pump I think is the original one fitted to the 'van in 2007. It has had one failure and that was the gasket sealing the pump assembly.

 

[TJBi]

The diaphragm type of pump, which is what the Flojet is, should last almost indefinitely. The point of failure is the diaphragm itself which is easy to replace.

My Shurflo pump I think is the original one fitted to the 'van in 2007. It has had one failure and that was the gasket sealing the pump assembly.

And in my similar case the leaking gasket resulted in water visible in the area of the pump. The OP indicates that there is no visible leak, so as you said above, very possibly an airlock.

 

[r4dent]

Have you checked the dump valve, just in case it's tripped.

Can you advise where the valve is,is it on the pump itself or close to the inlet or outlet

The dump valve is part of the hot water system rather than anything to do with the pump.
A slow leak on the dump value would cause a small pressure loss causing the sensor to switch on for a short period as per post 3 in this thread.
Normally the dump valve is used by the owner to drain the boiler after a trip
ACTION tell us how you drain the boiler after a trip.

Manufacturers use different type dump valves in different locations. Without knowing details of your van we cant help you find it
ACTION ell us Make /model / year of van & Make Model of heating system


ACTION Have you done any on the action I recommended in posts 3 & 4

 

[JonnoR]

The dump valve is part of the hot water system rather than anything to do with the pump.
A slow leak on the dump value would cause a small pressure loss causing the sensor to switch on for a short period as per post 3 in this thread.
Normally the dump valve is used by the owner to drain the boiler after a trip
ACTION tell us how you drain the boiler after a trip.

Manufacturers use different type dump valves in different locations. Without knowing details of your van we cant help you find it
ACTION ell us Make /model / year of van & Make Model of heating system


ACTION Have you done any on the action I recommended in posts 3 & 4

No further actions have been undertaken as we were away and used local water for a brew etc. Will undertake actions in Posts 3 and 4 later today and will advise.

 

[JonnoR]

The dump valve is part of the hot water system rather than anything to do with the pump.
A slow leak on the dump value would cause a small pressure loss causing the sensor to switch on for a short period as per post 3 in this thread.
Normally the dump valve is used by the owner to drain the boiler after a trip
ACTION tell us how you drain the boiler after a trip.
Only drain the boiler in the winter by opening the dump valve and letting all drain out

Manufacturers use different type dump valves in different locations. Without knowing details of your van we cant help you find it
ACTION ell us Make /model / year of van & Make Model of heating system
2020 Auto Explore (Webbs of Reading PVC) - Truma Combi (e)

ACTION Have you done any on the action I recommended in posts 3 & 4

Filled as per instructions - no change, pump working - no spluttering, no water

 

[JonnoR]

Tank inlet pipe inspected - no leaks, No leaks inside the van around the pump. If there were to be a leak then surely the water level would be affected - which it is not. Pump working and feels like the diaphragm is working ie the motor is not free wheeling.

 

[JonnoR]

If you have a Truma heater it will be close to that, have you looked underneath the van when the pump is running?
p.s. if no other leaks then as the manufacturer has advised, a failed pump is probably the culprit, but two in two years seems excessive.

Dump valve - as you say is close to the pump and in good order. No visible leaks - but if there is one I bet its in an inaccessible place. The strange thing was that sys had been working perfectly for two days before. All I did was fill the water tank, then the pump started triggering on / off.

 

[r4dent]

Tank inlet pipe inspected - no leaks,

To cause the intermittent running described in your original post the leak needs to be in the pressurised part of the system.
i..e between the pump and the taps.

If there were to be a leak then surely the water level would be affected - which it is not. Pump working and feels like the diaphragm is working ie the motor is not free wheeling.

24 hours of intermittent running can be caused by a slow leak of less than half a cup of water, the drop in water level would not be evident.

Filled as per instructions - no change, pump working - no spluttering, no water

This tends to eliminate an air lock.

One further (unpleasant) check.
With the pump running and all taps closed
Remove the shower head.
Open the shower cold tap.
Suck on the shower pipe.
(I said it was unpleasant) .

If you do decide to replace he pump, test it before ordering a replacement. There are repair kits available for a lot less that the replacement cost.

 

[JonnoR]

To cause the intermittent running described in your original post the leak needs to be in the pressurised part of the system.
i..e between the pump and the taps.


24 hours of intermittent running can be caused by a slow leak of less than half a cup of water, the drop in water level would not be evident.


This tends to eliminate an air lock.

One further (unpleasant) check.
With the pump running and all taps closed
Remove the shower head.
Open the shower cold tap.
Suck on the shower pipe.
(I said it was unpleasant) .

If you do decide to replace he pump, test it before ordering a replacement. There are repair kits available for a lot less that the replacement cost.

So, did the above, Not that unpleasant compared to petrol / diesel, a small amount of water came out and then nothing leading me to believe that the pump is the issue. Will talk to the manufacturer to try and get another from them, just out of warranty and / or a spares kit to try and fix the issue. Will keep you posted thanks for the feedback