zip inline water heater

[bullseye123]

this refers to a earlier posting ive bought a zip inline instantaneous water heater 5lts a min .. ive tested it out with a ordianary handset, the temperature is a max 55c but on testing by thermometer it only reaches 37c and its a direct cold feed into the heater...the flow is good.will there be a problem with the heater itself or is this normal with this kind of heater..

kind regards

 

[Madrab]

it's normal bullseye and will vary with the cold water temperature too. The 55DegC would be optimal at a given water flow rate and at max setting I would think though I believe these heaters would be factory set at 38DegC? What model is it?

 

[bullseye123]

cex-o oversink model

 

[Madrab]

OK, so according to the specs it will raise the incoming water temp by 25DegC @ 5 l/min at 9.6Kw (Δt = 25°C) or 4.1 L/Min @ 7.2Kw.
So if your incoming cold water is say 15DegC, the output will be approx 40DegC @ 5 l/min @ 9.6Kw.
To get it any higher you would need to turn the hot tap down to slow the flow.
I assume you had it set at 9.6Kw at installation time and you have it set to the Max of 55DegC?

 

[bullseye123]

spot on with all that..thing is ive just done a trial with cold water in and a shower handset on the output to see wat flow I get and the right temp to see if its compatable with a fixed head in the ceiling...ive got the flow but 5deg short on temp for a normal hot shower

 

[Madrab]

Unfortunately then you're at the limit of your installation and it will get lower as winter sets in and the cold water inlet temperature drops I'm afraid

 

[Charnwood]

The brochure for the Zip Inline CEX-O says the temp can be set to between 30 and 55°C.
It also states that the power rating can be set at installation to 6.6 or 8.8kw.
Could that be an issue?

 

[Agile]

I hope you realised when you bought it that its hardly suitable for a proper shower. 4 li/min will wash you but not as most expect a boiler supplied shower to be.

I would have expected they are really designed primarily for hand washing!

 

[bullseye123]

im going to put a shut off valve on the hot water to act as a tap then see how far it has to close to reach a decent temperature then hopefully still got a good flow...if it don't work only option is a electric shower then there will be a water heater goin cheap

 

[Agile]

A 24 kw boiler will give about 8.5 litres per minute at a good temperature!

You can work back from that flow rate according to your heater power.

So 8 kW would give a little less than 3 li/min for example.

 

[bullseye123]

ok then...ive put an isolating valve on the hot outlet to act as a tap so to reduce the out flow and hey presto its just as the bloke at zip sed...no different to a electric shower...works perfect got the temp up to 51deg could go higher but it was scalding and the flow was very generous,that was wif a ordinary 75mm shower head so there shouldn't be to much difference with a shower valve and a 140 fixed shower head ..

 

[bullseye123]

just been looking at fixed shower heads and most haf got 1.0 bar or 0.5 bar mp...im not clued for bar pressure so can anyone shed a light if I haf mains pressure to this heater wat bar rating would that be and am I right in thinking a reduce flow on the hot outlet would reduce the bar to the shower head cos if im not getting min 0.5 bar it wont work.

kind regards

 

[Agile]

Hens coming back to roost?