Like most of us, I have the skills to do most plumbing jobs, just lack the knowledge of the system. Can anybody advise me the best way to add a booster pump to my hot water system? I know I need a flange to prevent ingress of air, and I need a prv to protect my shower pump (integral), and I know where I will be able to fit the pump. This is where it gets tricky! Most of the pumps I'm looking at have 4 ends to them, but some have 2. I will be fitting it above my tank and I haven't got a clue which pipes I should be hooking this up to. HELP!
Depending on your tank layout (i.e. where it is with respect to the cold cistern etc) you may get away without a flange. Many of the pump fitting instructions specify an essex flange as the first choice, then surrey, then a tee off an angled pipe from the top of the tank etc in decreasing order of desireability. The more powerful the pump the more important this becomes. Also if you get lots of air in the system as it is then it is also more important.
Pressure reduction valve? Depends on the way you are planning to set it up...
Inline filters on the input would be good as well (a decent pump will probably come with them)
Below the hot water cyliner is preferable to above although it its the distance to the water level in the cold water tank that matters most. If this is too small you may need a "negative head" pump.
The pumps typically have 4 connections as you say, hot and cold in, and hot and cold out. The ones with only two are designed for boosting just a single supply only (like boosting pressure to a gravity fed hot supply so that it can be more effectively mixed with mains fed cold (and you *may* want a PRV on the cold mains feed there), or, a single can be used after the shower mixing valve to pump the blended water to the shower head.
The type with four connections are designed to boost low pressure hot and cold at the same time. To install these you take a hot feed to one inlet from your hot cylinder (via the flange or whatever), take the cold feed from a dedicated pipe from the cold tank to the other. Then take the outputs to the shower, or other taps as required.
If you are just pumping the hot water (usually because your cold water is supplied directly at mains pressure) then you need a single impellor pump which has 2 water connections.
You connect the input connection to the flange on the cylinder. You connect the output to the shower/bath tap.
The twin impellor pumps have a separate channel so that the cold water also gets pumped. This is necessary if the shower/bath cold tap are fed from the tank, rather than from the mains.
Hi guys, thanks for your reply. Apparently, there is a Warwick/Warwix (I've seen both spellings) flange to let me fit above the tank, simply by replacing the vent pipe from the top of the tank. To me, this is preferable for 2 reasons: first, I don't like the idea of cutting into the tank; second, I haven't really got the space to fit it anywhere else.
The challenge I have over the piping is this: I have 2 feeds on the pump, 1 in 1 out. I run the inlet pipe to the in side of the pump and I run the outlet to the original feed entry of the tank (I'm looking to boost pressure throughout the house, primarily to a large washing machine). Where does the vent line go? Sorry if I'm appearing dense, but this has definitely got me confused.
I need the prv because I already have a power shower fitted and the extra pressure will blow the seals in it.
Incidently, the pump will probably be 2 bar, as I am intending to build an en-suite and use the pump to feed the shower in there.
These are basically the same as a surrey flange. They fit into the boss at the top of the cylinder and provide two outlets. One intenede for the non pumped HW that comes from the side, and a second intended for the pump feed that comes from the centre tube at the top which ensures this water is taken from a couple of inches down from the top of the tank and hopefully away from any air.
Yup - if you don't have an essex flange already fitted (many modern cylinders come with them factory fitted and blanked off) this is a simpler way to go.
So you are not planning to use the side connection of the flange for feeding unmpumed hot water anywhere then? If so you can connect this to the vent pipe, and then feed the pump from the top connection on the flange. Feed the output of the pump into the remainder of the pipe that used to come from the top of the cylinder (and had the vent on it)
Could you not feed this from the side connection of the flange along with the vent connection?
Thanks for the reply, John. I've been trying to get my head around this, but I don't think it will make any sense until I see the flange and pump together. Wish me luck!
- that might help it make sense. Basically the hot water for the rest of the house goes up the base of the flange and out of the side port, the water for the shower comes up the dip pipe and out of the top port. This ensures the shower (i.e. pumped) water gets takes from a little bit down from the top of the cylinder and hopefully away from any accumulated air bubbles.
The shower pump will typically have push firt connections for ordinary
15 or 22mm pipe. These will usually be on the end of short rubber hoses to help isolate any noise and vibration from the pump. So all you need is a pipe from the top connection of the flange to the inlet side of the pump.
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