Vidaxl heat exchnagers

[Spedley]

Has anyone experience of the vidaxl heat exchangers? I'm currently using a 130k BTU Certikin model (hexagonal) but my pump can't push the water through fast enough. It seems designed like this to minimise flow restriction because when I bypassed the sand filter with a pump 20% larger the outlet water still rises by about 3'C.
My best option so far is another heat exchanger in series with the first which should solve my problem (the boiler turns off every 4 mins for 2 mins), however a new 60KW vidaxl heat exchanger is within my price range if it is more efficient and it would take less space which is running out.

Has anyone got one of these and can tell me details of their setup?

[Teapot]

I have no experience with that manufacturer but have seen a number of them fitted. I can see they are very reasonably priced. Are you using a salt chlorinator, I ask as these are stainless steel and salt water maybe a problem.

My preferred heat exchanger are the Bowman range, the biggest difference with Bowman is the water enters and leaves at the ends, rather than the sides meaning the lowest pressure drop and therefore the highest water throughput. They are made in many materials from SS and Cupro-nickel to Titanium for the harshest environments. I fitted one on the solar ones a couple of months back as the solar ones are slightly larger meaning a faster warm up and lower boiler temperature saving money where possible and the customer was delighted with the big improvement over the pathetic Certikin one just like yours.

I understand budget constraints but would love to hear how you get on if you do fit the Vidaxl unit.

[Spedley]

Thanks for the info. Confirmation that the Certikin models aren't great may be good enough.
I'll do a bit of overtime for the next few days and go for the 75KW vidaxl model (£120). When I put the boiler in I made a re-circulation loop just in case the heat exchanger was too good so an over-specced H/E shouldn't be a problem.

... unless anyone else posts differently!

[Spedley]

VidaXL got back to me with details of the 60KW heat exchanger.

Thermal Output 200.000 BTU/hr (60KW 51.00Kcal/h)
Hot water flow 30L/min
Pressure Drop 1.7Ft.
Pool water flow 250L/min
Pressure Drop 4.5Ft
Heat Transfer surface 4.8Sq. ft. (0.4m)

My hot water flow is higher than that but no way can I get my pool water flow that good.
I'll measure flow tonight and do a few calculations but I don't think the 75KW version would be good enough.

[Spedley]

I checked my 500W pump (1.5" hose type plumbing) and I'm getting about 105L/m through the filter and H/E and 130L/m bypassing the filter.
Nowhere near the VidaXL 250L/m requirement!

I also just realised that Stainless Steel is a very poor heat conductor (not as bad as titanium) at about 12% that of copper . Are there alternatives for non-salty pools or are Stainless and Titanium the only options?

[Teapot]

Take a look at bowman, Cupro nickel. The slower flow rate won't hurt anything it just means the water will transfer at a slightly higher temp. Compare that to the certikin!

Even the 105 litres is way too fast for good filtration for that size of filter. I do only slightly more through a 24" triton.

https://www.ejbowman.co.uk/products/Swi ... angers.htm
http://www.ejbowman.co.uk/pdf/Bowman%20 ... ss%20A.pdf
You may have to do a little more overtime.

[Spedley]

I just stumbled across these today. A bit pricey but if the performance is as claimed then maybe value for money
https://www.ebay.co.uk/itm/122009136486

Claims it can achieve heating with only 40L/m vs nearly 200L/m for tubular heaters. I'll have to research a bit more ... so many options, so much money! (don't mind paying if it works but fitting it only to find it isn't as expected is out of my budget!)

[Teapot]

Yes I have seen those, not used one but what puts me off is when an advertiser down talks and produces bogus data on tubular heat exchangers. Whilst we both know Certikin fail to perform, I have experience with Bowman and they do. I used one of their solar range on a HE gas boiler and it was fantastic compared to the Certikin. begins to heat the pool much earlier because of the larger area, OK maybe a bit overkill but it's what I will be using on mine when I re-do the heating.

http://www.ejbowman.co.uk/pdf/Bowman%20 ... ss%20A.pdf

[Spedley]

I've made a decision and now I have to make it work! My budget doesn't stretch to a proper H/E and I can't get the required flow with my current pump. Costs down this route are too high or the wait for 2nd equipment is too long.
So I've gone for a non-pool H/E. It is stainless steel with copper solder. This presents the problem of metal in the pool, however I do add copper in the algaecide so I'm hoping it won't be much of a problem. Also, this is a small children's pool so perfection is not required.

I've ordered one of these http://www.ebay.co.uk/itm/331858111056. It claims 90KW with a maximum flow rate of just 67L/m which would allow me to use my smaller 400W pump that is better for my filter. I'll plumb it with a 'bypass' to limit the flow through it for pool water and my heater pump is rated 50L/m max so shouldn't be an issue. I'm hoping for at least 50KW output, even with pool temps over 30'C (86'F) which would allow me to run the boiler at it's maximum 175kBTU.

I'll let you all know how I get on when I've worked out a decent connection and got it plumbed in.

[Teapot]

Please do, I'll be interested to hear how it works out, I am sure it will be a big improvement on the current setup.

[Spedley]

I can confirm that it works well (just in time - an ebay heat exchanger appeared the day after I bought this one and that ends tomorrow).

It cost me about £40 to install so £120 total cost. I've done a 'proper' job after quick testing but it turns out the heat exchanger performs better than expected. I didn't expect the quoted 90KW output unless I put exactly the quoted 67L/m through both heat and pool feeds. In fact, my expectations were quite low.

Anyway, I think my hot feed is about 50L/m max and my cold feed is only about 30L/m but my 40KW boiler struggles to get to 50'C (should be 85'C with 65'C return feed)
I'll get it sorted well over the next few days and do a write up on a new thread.

[Teapot]

Great to hear Spedley, look forward to the update