Shower pump question

[BrianI]

Hi Guys,

I would like some advice for our shower pump. I have bought and installed a watermill PR50D regenerative pump, but I will give a brief overview of what we had done.

Several years ago we had a Mira mixer shower. We had a reasonable flow of water but it was always very hot, it was hard to get it to be comfortably warm. When we took the old bathroom out we capped off the pipes in the loft and have since recently decided to install a new shower.

We went for a thermostatic mixer (gainsborough GS500) shower in the hope that this would solve the 'old' temperature problem. It does seem to have done this but the pressure is quite low, we get a useable flow of water through but it's far from anything that would enable a quick 2 minute shower in the morning. So I decided to put a pump in the loft.

I should say in advance that with the pump not connected to the electricity the shower behaves exactly as it did previously so I don't think that there is a problem with any water flow through the pump. There is a large water tank in the loft dedicated for the shower. The waterline of the cold water tank is above the pump but the bottom is not. I don't think this is the problem (at least at the moment) but I thought I should let you know. The hot water pipe runs vertically from the hot water cylinder into the loft. The supply to the shower is tee'd off with the pipe continuing up and over for the overflow and also to avoid any air getting trapped (?).

I cut the pipes in the loft to the shower and connected the pipes to the pump. I ran the water through the pipes for 5 minutes and then turned on the pump. I could hear a noise which sounded like the coils were engaged, but the pump didn't kick in. Smoke then started to come out of the pump. I turned it all off. Confirmed that the water was still running through the pipes and then tried again with the same effect.

I then disconnected the pipes and then with the pump plugged into the mains I (very briefly) blew through the inlets (each in turn) and heard the familar pumping sound kick in.

Does anybody have any suggestions? I would really appreciate it.

Regards,

Brian

 

[SUPERPLUMBER]

if your hot supply to the loft goes straight up, you;ll need to install an anti gravity loop ( a downward bend from the tank then back up to the loft) .

if your hot pipework is going up and over and you plan to put your pump in the loft you'll need a negative head pump due to the low flow rate from the tank since your "head" of water will be severly reduced.

some pumps work on flow rate and use floats to activate them and but negative head pumps (well the last one i fitted Stuart turner watermill) work of a pressure drop when the shower valve or tap is turned on.

Also when installing neg head pumps you still need at least 500mm of head but you'll need to check the install instructions.

 

[BrianI]

Thanks for the reply superplumber.

The pipe goes up to the loft and also down (I assume to the hot water taps downstairs and in the bathroom). What does the anti-gravity loop do? Do I need it because of the pump?

The pump says that if it's for a neg head I would need to buy a switch. I assume that the switch is just to turn it on and that the pump can act a neg head pump. The pump does activate, or at least the coils do, it just doesn't pump. If it didn't activate then I would install the pump in the airing cupboard. But because it does activate but doesn't pump, I wonder if there is something wrong with the pump.

I am inclined to install it in the airing cupboard - just to see and I don't want a switch to press as I don't want to recess it into the wall and I don't want the air tubing on the outside of the wall.

Thanks again.

 

[BrianI]

I have uploaded a picture to imageshack to sketch the diagram in case it helps anyone solve the problem.



I have been calling grundfos watermill all day without any luck. Has anyone dealt with them before. Also there was water in the pump before I installed it, is this normal?

Brian

 

[heytesto]

Don't take the hot feed from there Brian, you will be dragging air down the open vent.

The hot water connection should be off the top of the cylinder with a surrey or warix flange.

 

[seco services]

its installed wrong.

has the mi not tell you how to install it ?

 

[heytesto]

Smoke from the pump isn't good. It's probably had it.

I would site the pump in the airing cupboard, bring down a dedicated cold supply from the tank and use a Surrey flange for the hot. Take the pipework up into the loft and fit manual air vents, so that the system can be primed. Providing you have a metre head of water above the shower head, the pump should kick in. If it doesn't and you are using a hose and riser rail, take the head out of the rest and drop it down, turn on the shower and the pump will kick in. Replace the head in it's holder and enjoy.

 

[BrianI]

Yeah - that is what I have been hearing from a couple of people. I will do that. What's the difference between a surrey flange and a warix flange? I can't find any links on the web. Does anyone have a picture of an anti-gravity bend?

Thanks guys,

Brian

edit: There were no instructions in the box. I just had a go. I have installed a few sump pumps in my time so I thought I would just give it a go.

 

[Richard C]

As already said, the installation is completely wrong; the pump, even if a negative head, must be installed below the bottom of the CWS tank or it won't work properly. Best place is in the bottom of the airing cupboard, with as short a feed pipe run as possible; an Essex flange can also be used this preferred by the majority of pump manufacturers.

This guide is for Salamander but it covers most types of installation, including antigravity bends, vents, check valves etc, but the principles are mostly the same for all pumps;

http://www.salamanderpumps.co.uk/Download/instructions.pdf

Read it & you should see where you’re going wrong. I wouldn’t run the pump any more or you will fry it; in fact you may already have done but only time will tell.

 

[heytesto]

There you go, Richard C's given you all the info you need.

Essex flanges are far more awkward to fit as it involves drilling the cylinder.

Down south, most cylinders are 1" female tappings and a surrey flange will do. However, up north they are generally male tappings and surrey flanges don't fit even with a 1" brass socket. A Warix flange does fit.

Otherwise, for simpicity use the teeing of the underside of a 45deg draw-off method shown in the Salamander pdf. (Not preferred, but ok)

 

[BrianI]

This is great guys, thanks for the support. It's good to get this advice, I wish I had asked earlier.

Thanks for the pdf Richard.

I'll let you know how I get on.

Brian

 

[BrianI]

Hi Guys,

I have a few questions again. Here are some pictures of my hot water cylinder. Will I get a standard fitting for that head? I really don't want to drill into the side of my cylinder. I am sure I will drill in the wrong place.





My shower is connected from the loft. So I would like to run the pipes into the loft and across to the shower. I will place the shower pump, as suggested, at the base of the my hot water cylinder. I will run the hot water out of the hot water tank to the pump then up to the loft and then take the water from the cold water storage tank down to the pump and then back up to the loft. The head of the shower is about 1-1.2m below the cold water tank.

Thanks in advance.

Brian

 

[Richard C]

As has already been stated, your going to have to change that top cylinder connection completely to allow fitting any of the top entry flanges, none will fit as the take off is currently configured. You could use a 45 degree take off but that’s just as much work &, personally, I would leave it as it is & fit an Essex flange which is really the best solution. They really aren’t as daunting to fit as they look, it’s cutting the hole that frightens most people off but as long as your above the heating coil & think about where you’re going to insert the internal take off tube so it avoids the immersion heater, it’s relatively simple.

Re the pipe work; it’s not just the position of the shower head that could put the pump into a negative head situation; any up & over pipe work from the pump to the mixer valve must be run around 600mm below the bottom of the cws tank or you could still end up with a negative head situation which will require a negative head pump; you need a natural flow of at least a 1 litre/min or you will have problems with the pump. Don’t forget you will also need vents at the very top of the h&c pipe loops & use only full bore isolator (gas) valves on the system, most gate valves will restrict flow.