Arrow Valves 'Pentaboost' booster pump solenoid replacement

[elemoine]

My flat is too high (4 floors) for Thames Water mains pressure. The builder fitted the above pump about 8 years ago. It now periodically 'dries up' and then eventually recovers, but for 10 or 15 minutes (usually mid-shower) no water is available. Arrow Valves tells me the solenoid valve needs replacing, but they are not able to send a technician until mid-July. They have advised me to order the valve (which I have done) and find a local tradesperson to fit it. But, so far I have been unable to find such a person. The pump and valve in question can be seen here: www.arrowvalves.co.uk/downloads_ss/btafcompactboosterseto&mmanual.pdf (valve on page 4). Is this rocket science? Could I replace this valve? Does it have to be done by a technician registered with some sort of qualification or can any reasonably competent person with a screwdriver do it? With thanks, as always, for any advice, EL.

 

[bernardgreen]

It now periodically 'dries up' and then eventually recovers, but for 10 or 15 minutes (usually mid-shower) no water is available.

These pumps can only provide water at pressure while there is water in the tank. If the shower is using water faster than the feed to the tank the level in the tank will drop. When the level in the tank gets too low the pump will turn off until the tank has enough water for the pump to restart.

There is obviously enough pressure to lift water to your flat but at low flow rate. Have you mentione this to Thames Water and asked about an increase in local supply pressure ? The alternative is to have larger supply pipe to your flat. I expect the builder used 15 mm pipe without any thought about flow rates needed for showers.

 

[elemoine]

Thanks bernardgreen. So you don't think the solenoid needs replacing? This problem has only just materialised (in the past 6 months). When I go downstairs to check the pump, lift the lid and trick the sensors into thinking that the water level has dropped, the water gushes in. The shower is not a 'power shower' and the pump should be able to supply water at the rate required by the shower - we checked this when the shower was installed. I now can't remember how many bar, but we did check to make sure. If not solenoid, what could it be? I know Thames Water is working on pipes all over the place, and they could have interrupted supply temporarily, but this many times over a 6-month period, always for only 10 or 15 minutes and without notice?
Thanks! EL

 

[bernardgreen]

If tricking the sensors that the level is low results in the solenoid allowing water into the tank then I would doubt there was a fault with the solenoid as it is responding to the sensors.

The data sheet contains this

Fast and accurate level control is achieved with a solenoid valve. Electrodes provide on/off full flow control with 60 mm delayed action.

what is "60 mm" as a delay ?

Have you seen the tank less than full and the water not coming in when it should be ? That would suggest a valve problem or a sensor problem.

Is it possible to look at the tank while the shower is running and see if the level drops below the minimum level and cause the pump to shut off.

How clean are the electrode sensors ? Are they two electrodes per sensor ? Are you tricking them by disconnecting the lead from the sensor ?

If there is any lime scale on the electrodes where they come out from the insulator then damp in that limescale can give a false indication that the electrodes are underwater and that the tank is full when it is not. Disconnecting the lead will remove this false full indication and thus open the valve.

A better test is to take water out of the tank until the start sensor electrode is uncovered and see if the solenoid then opens. There is likely to be a short delay in the controller before the valve is operated.

If the bottom electrode gives a false reading that there is still water when the tank is empty then the pump will run dry and if it has any run dry protection this will (should) operate and it may be several minutes before the pump can re-start even if the tank has filled by then.

 

[elemoine]

Hello. Me again. The problem with my water pump intermittently cutting out for 5 or 10 minutes continues, and is now getting more frequent. I've been able to observe it in operation / non-operation a couple of times now. It's not a problem with the sensors or solenoid, as when it cuts out, the tank is not empty. But, in non-operational mode both lights ('ready - timer' or 'low water fault') are both off and the pressure drops to below 1 bar. When the pump restarts, as it does spontaneously, it smells hot and the 'ready - timer' light comes back on, the pressure leaps up to nearly 3 bar and everything runs fine again. Could it be the capacitor or other part of the pump overheating? Could this be because the pump is slightly too small for the job it's being asked to do (supply water to a fourth floor flat)? As always very grateful for advice - I haven't had any luck getting a plumber to come and look at it and the company that made the pump charge a £200 call out fee, so if it's something simple, I'd like to fix it myself.
With thanks as always, elemoine