Will this destrat pump be okay for my Telford horizontal cylinder?

[jgc1457]

Hi all,

My first post so please forgive me if I get some of the terminology wrong!

We recently had a 240 litre Telford horizontal direct unvented cylinder installed. It has a single 3kw immersion (it came with two immersions, but we only had sufficient electrical power to the place it was being fitted to use one). At best we get probably 50-75 litres of water from it before it cools off, and Telford's technical department suggested we have a destratification pump fitted.

They said it must be bronze to avoid creating sludge in the tank over time, so I've found this one from Toolstation: DAB Evo VS Bronze Hot Water Circulating Pump 65/150 B - https://www.toolstation.com/dab-evo-vs-bronze-hot-water-circulating-pump/p44443

My idea is to ask our plumber to connect it to the same timeswitch as the immersion, so that it runs while the immersion is on (around 2 hours per day).

Would this pump, and my idea of fitting it to the same timeswitch, solve our problem? Grateful thanks in advance for any suggestions or advice!

Jodi.

 

[EvilDrPorkChop]

Yes that pump is correct and yes fitting it to the time switch as you suggest would be fine.

 

[jgc1457]

Brilliant! Thank you EvilDrPorkChop, much obliged -- and an awesome name if I may say so 😁

 

[chris watkins]

The problem is as likely to be with the heat up time as with stratification, 2 hours is never going to be enough time to heat 240 Litres. To give you an idea a 250L vertical with 1 x 3kw would take close to 4 hours to heat, your horizontal will take longer, check the MI's (instruction) they should give an idea.

P.S. the pump is still a good idea & you can use a stainless one as well as the bronze either will need to be WRAS approved for secondary hot water systems.

 

[jgc1457]

The problem is as likely to be with the heat up time as with stratification, 2 hours is never going to be enough time to heat 240 Litres. To give you an idea a 250L vertical with 1 x 3kw would take close to 4 hours to heat, your horizontal will take longer, check the MI's (instruction) they should give an idea.

P.S. the pump is still a good idea & you can use a stainless one as well as the bronze either will need to be WRAS approved for secondary hot water systems.

Hi Chris, thanks for the heads up -- you're right, it'll need a good bit longer to heat the whole tank, but according to the manual it loses the equivalent of 1kWh heat per day, and we would only rarely use a large proportion of the water for a bath, so I'm thinking 2 hours (6kWh) each day might work but I'll use trial and error. The main thing I wanted to check is whether it is sufficient for the pump to run for the same amount of time as the immersion or whether it needs to run for longer and therefore would need its own power supply and timeswitch, but if I can run it off the immersion's timeswitch, so much the better.

 

[chris watkins]

Hi Chris, thanks for the heads up -- you're right, it'll need a good bit longer to heat the whole tank, but according to the manual it loses the equivalent of 1kWh heat per day, and we would only rarely use a large proportion of the water for a bath, so I'm thinking 2 hours (6kWh) each day might work but I'll use trial and error. The main thing I wanted to check is whether it is sufficient for the pump to run for the same amount of time as the immersion or whether it needs to run for longer and therefore would need its own power supply and timeswitch, but if I can run it off the immersion's timeswitch, so much the better.

If you are only heating part of the cylinder i.e. say the top 1/3, then why are you thinking of adding a de-strat pump to mix it all up, you will just end up with a cylinder full of luke warm water?

 

[jgc1457]

Good point -- the plan is to use the immersion for as much as needed to keep the whole tank at or above 65C -- some days (most days) it will need longer than 2 hours I'm sure, other days not so much, assuming the figure from Telford (1kWh equivalent heat loss per day) is correct. As I say, I'll just need to use trial and error to make sure I don't end up with a cylinder of luke warm water, but thanks for pointing it out as it's not something that had previously dawned on me

 

[king of pipes]

Think it will be a waste of time to be honest horizontal cylinders never compare to a vertical one for hot water capacity. Kop