Hot water recirculation

[RolandK]

Hi there,
I am a what I'd call a competent DIY plumber but need a bit of help on this one!!!
Although our house is not large, due to the pipe runs originally installed water takes too long to reach the hot water taps in the kitchen and utility/downstairs cloakroom. I was thinking about one of those recirculating pumps like a Grundfos Comfort. I undersatnd this needs a new return pipe to be installed or I did read somewhere that they could use the cold pipe as a return??? Also, we are all electric heating our large hot water tank overnight with Economy 7. I was wondering if the constant recirculting of cooler water during the day will cool the tank too much so we run out of hot water during the day.
Hope some of you chaps have some experience of this?

Cheers, Roland

PS. Happy New Year!!

 

[prs1]

How long do u have to run the hot in the kitchen before it becomes warm?
you can use your cold feed on your cylinder for the return if you add a non return valve,but u would still have to install a new lengh of pipework from here to as near to the kitchen sink as you can get (1 meter).
Also allow for insulating it well and last but not least it would need a pump.
Personnally i would be looking for a shorter more direct route for a straight feed from your cylinder as this type of set up is not normally needed in a normal sized house,usually large properties.

 

[RolandK]

Thanks prs1,
it takes a minute or so for the hot water at the sink to get hot and longer further out at the utility room. Takes about a minute at the bathroom basis too! I like your idea of a more direct pipe run. At the moment the hot outlet from the tank goes up into the loft and is tee'd off the vent pipe. (A seperate Warix flange feeds the shower pump). It then crosses the loft to a cormer where it goes down to the bathroom where it doubles back on itself to the bath! A tee from here goes down to the kitchen where another tee goes across and down to the utility! Seems to me the plumbing was put in after the floors were laid and they didn't want to take them up again.
Cheers,
Roland.

 

[Bernie2]

The usual way of course, is to take a pipe from the furthest away fitting i.e. sink or basin usually, and return it to the cylinder, checking for any dead legs.

Stick a pump on it by the cylinder, so it whizzes the hot water around and you get virtually instant hot water everywhere. The problem is, you have to insulate the pipe well to save heat and a time clock for the pump is recommended, so its not running all the time.
You can of course do a gravity circulation system but you have to have the room for it.

 

[stevetheplumber]

with the layout you describe you could have a gravity loop by running bach from the hot supply under the bath through the floor and in to either the return tapping if you have one or the cold feed b ut if your having the floor up just shortening the run would have toe same effect

 

[Plucky]

A quick tip here to minimiise heat loss is to link a pipe stat on the hot water return, about 3 metres away form cylinder. Set its temp slightly below desired temp of cylinder and the pump will only come on when the water in the pipework has become cold.

 

[RolandK]

Thanks for the advice. I'm going to take a look at by how much I can shorten the pipe runs and if I can't or it's too much upheaval I'll go for a pump. Just to repeat one of my original concerns, If the immersion only works at night will the recirculation make the water stored in the tank get colder sooner? Guess I want my cake and eat it!!

Cheers,
Roland

 

[stevetheplumber]

Thanks for the advice. I'm going to take a look at by how much I can shorten the pipe runs and if I can't or it's too much upheaval I'll go for a pump. Just to repeat one of my original concerns, If the immersion only works at night will the recirculation make the water stored in the tank get colder sooner? Guess I want my cake and eat it!!

Cheers,
Roland

obviously yes it will loose heat when circulating

 

[Blackcatgas]

dont forget that it will need tobe a bronze pump, x2 the price of a normal ch pump!, if you can then lag the hot water and retun pipe in its entirety (sp).

 

[Plucky]

Have just installed a big system in new biuld house, 4 bathrooms utility and kitchen and I was able to lag the complete hot water loop in 19mm thickness lagging (havent lagged spurs to outlets) there is barely any heatloss. I have also installed pipestat to prevent pump circulating when unecessary, All outlets have hot water within 4seconds

 

[Quiz]

Can you still buy the single feed bronze pump with a flow switch? attach this to your hot water pipe and when you open a tap, the pump starts and speeds up the flow to the tap?