I have a problem with a Salamander CT50 shower pump. It's running a bath/shower mixer. The pump is sited underneath the bath and the run to the HWC is approximately 4-5 metres in 22mm on the same floor. The pump is the first device in the pipe runs from the CWS and HWC. The pipe runs continue to feed the toilet and basin and tees off through the ceiling to feed the kitchen. The pump will only start if the mixer is turned to cold. Once running the mixer and temperature controls work fine. There is a samll inverted loop where the feed pipes come out from under the floor at the tap end of the bath and run along the wall at approx 8" high and then drop back down again to the pump at the back of the bath. Any ideas?
Bad plumbing? the pump ought to have dedicated h/c feed. Ideally it should be sited in the airing cupboard at the base of the cylinder.
I agree, rip it out and do it properly. That's what I intend to do. The pump does start if the hot is turned on at the sink and turned off again. It's all withing Salamader's recommendations apart from the inverted loop. The pump doesn't has to have a dedicated supply provided the "tee off to the pump is the first call". The pump does not have to be at the base of the cylinder. "The hot supply pipework to the pump is maximum 5 metres in 22mm
"it's all withing Salamader's recommendations apart from the inverted loop. The pump doesn't has to have a dedicated supply provided the "tee off to the pump is the first call". The pump does not have to be at the base of the cylinder. "The hot supply pipework to the pump is maximum 5 metres in 22mm" True, but there is OK and there is BEST practice. If it ain't working look at the plumbing. Thats where the problem lies.
Agreed, but there is no room to site the pump by the cylinder, so what does everyone else do when they come across this common problem.
Try a different shower/pump combination ie an Aqualisa Quartz with the pump in the loft, a negative head pump etc. As regards your current set up try and keep the pipe runs to the pump straight without anything else teeing off them. You must have an airlock or poor flow which is preventing the pump sensing water movement and therefore turning on.
It is not the best way to do this salamenderw ould call it the least preffered way. i had a fault similar to this two weeks ago and all I did was get my mouth round the hot tap and suck. Sound grim but it worked and I got paid.
The system isn't airlocked though I will check again tomorrow. Changing the pipework isn't an option at the moment as the existing section I have used is underfloor and the customer doesn't want carpets lifted. Once the pump starts everything is fine, but it only does it once the hot tap at the sink is turned on and off. Would it be possible to fit a negative head pump in the current location to overcome this? I ask because Captain Leaky's advice about the problem being in the plumbing seems most likely. I don't think there is sufficient flow to start the pump.
What happens when you switch on the bath without power to the pump? Do you get a reasonable dribble out of the tap/shower? I have put in showers, where you have a long up and over configuration, which have allowed a decent flow rate through necessary to start the pump. So a down and under configuration even of 4-5 metres should be OK. I would be suspicious of the inverted loop, it could trap enough air to block the gravity feed and so not start the pump but allow the pumped feed through without dissipating the air lock. You talk about turning the hot tap at the sink on. Is this supplied by the pump?
If the cold trips the pump the hot should also. You have you got any kind of flow restriction fitted? What about the filters in the flexi pipes? have you tried disconnecting the input to the pump at the hot side to see if you are getting flow. I doubt it is -ve head if the cold runs fine and for that matter the basin which will be higher. Sounds like a blockage, air lock or pump fault to me.
You can easily find out if it is a pump fault by switching it round and see if it still fails to start. Air or very poor flow in the system is the likely culprit
Air or very poor flow in the system is the likely culprit It looks like you're bang on. I had a natural flow rate at the showerhead in it's highest position of barely 1 litre/min. I took your advice and went through all the plumbing again. One thing that I had not done was drain down and clean out the CWS tank prior to installation. I have poked myself in the eye several times now that I have followed Salamander's guidelines and done it. The insides of the tank connectors were heavily corroded and had effectively imploded on themselves so the bore was reduced to about 8mm on both connections. I haven't fitted new ones yet but I will this afternoon and I'm hoping that it will be problem solved. Being selfish I will spoil everyone's fun and call myself a muppet before some smartarse get's there first. Thanks for everybody's advice.
Not a Muppet, you are learning, put it down to experience and get it right next time. If you mess -up again then you are a muppet
The learning curve continues. I've changed the tank connectors and the problem still exists. Flow to the pump is excellent. Flow through the pump, mixer then diverter seems to be the problem. Salamander don't think the small inverted loop is causing the problem and have recommended fitting an RCM3 negative head conversion kit to each outlet which works on pressure drop. Has anyone used these. My thoughts are that I have a cheap pump and a cheap shower valve, both supplied by the customer. Natural flow throught the valve is poor and the flow switches in a £90 pump don't seem to be up to much either.
Sorry, unlikely to be pump or valve, I have installed shed loads of CT50's and yes , it is a basic pump but they are usually trouble free and reliable.
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