Baxi 105e - Luke warm DHW continues....

23 Mar 2006
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United Kingdom
The Dhw on my Baxi 105e isnt getting as hot as it used too.
Having posted on here previously on the same issue i have followed the advice and changed the dhw temp sensor and the plate heat exchanger after flushing the system out. All to no avail.

When running on c/h the water temp indicated on the front reaches 80 deg. Upon dhw demand initial dhw temp is good but after a few seconds the temp indicators on the boiler drop and the dhw does as a consequence?? The boiler temp holds at 60 deg leaving the dhw at a little warmer than luke warm.

The DHW temp control is set to max.

Any thoughts welcomed.
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I thought about the divertor valve and isolated the ch system via the valves at the boiler flow and return. DHW still does same.... However since last post i have noted that the boiler gets up to temp when dhw flow is reduced and the as a result the dhw temp increases.... However it used to cope with full flow.... according to the wife.

I am wondering if i should measure the flow rate of the dhw (Kitchen tap full bore). Maybe it is in excess of that which the boiler can cope with... especially as the cold feed seems mighty cold at the mo....
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If the boiler is cycling then it could be a scaled plate heat exchanger.

He has already changed this...

I would be checking that you are getting the correct gas pressures... might be more than you want to tackle tho!

If the tap is flow at more than say 10 ltr/min then it may be too much but from a kitchen tap this is usually not the case...normally the bath that this is a problem.
The kitchen tap does have a large flow rate similar to a bath tap.... Bath tap... same problem.

I will check the flow rate.
Check your flow rate and temp difference first. Do you have any mixer taps or a shower? I have had a similar situation, no pass down c/h and heat from h/w outlet but only look warm at tap and it was the mixer allowing cold to mix in with the hot.
Hi, I am having exactly the same problem, if I run the hot water slowly it will heat up to around 60 however if the water flow is increased then the tempreture drops cold, even though the burner is on high. The DHW HeatPlate Exchanger has been changed, the thermister and microswitches are all ok and are operating correctly. The CH works fine.
Any ideas?
I concur with flow rate check first. This is, after all, a boiler which provides 12 litres DHW per minute @ 35°C rise. As incoming mains is about 7°C at the moment, if you are attempting to get more than 15 litres per min you will be lucky to get water at body temperature from the tap.
Fruitcake just resurrected a 4 year old post! You other guys need to check your plate heat exchanger isn't blocked with debris! ;)

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