dhw problem on combi boiler

Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
right guys i want no wise cracks plz

i have a problem concerning my combi boiler wait for it "ideal logic +30" so i know what your going to say lol

i had it installed march 2011 up untill now i have had no problems what so ever been great an very efficient

3 bed terrace 1 bathroom

the problem is the last 2-3 months i have noticed that i have to turn down my bath tap half way or less just to get my desired heat (takes for ever now)compared to the 1st year an a half with the tap open full was great an boiler set 55 deg even throught last winter which the weather now is a bit warmer here in n.i than last year .
my water pressure is no more or less than first installed

got all my plumbing an taps checked before ringing ideal so i wasn't wasting anyones time an plumber said the mains pressure was spot on
which i never even asked what it was at , he used guage

so ideal sent an engineer out there today he changed a turbine i think its called with new filter an seal which to no avail still same prob so he recommended installing a prv an set it to 1.5bar as i have to much mains pressure going throught the boiler but he never tested the mains pressure
i tried explaining to the engineer that i had no problems before with hot water an flow till the last 2-3 months so how does he justify drop the pressure even more to me thats trying to hide my problem

when i explained to ideal on the phone my situation they said either heat exhanger needing flushed or replaced they will organise engineer to check ,flush or replace under warranty

so what do i do put a prv on an set it to 1.5 an suffer **** hot water flow or ring ideal an give off or do i try an flush the heat exchanger myself mind i aint gas safe reg'd

thanx in advance
 
Sponsored Links
Joined
5 Dec 2012
Messages
694
Reaction score
96
Location
Surrey
Country
United Kingdom
Max dom hot water flow rate is 12.4litres/min with 35degC rise from cold.(at this time of year about 8 degC hot out will be about 43degC if you want it hotter flow rate will have to be less. if this is not the problem then you may have a partially sludged heat exchanger, but if you have a magnaclene then heat exchanger will be ok. go to this site and get someone to check you flow rates and temps.
http://www.gassaferegister.co.uk/registersearch/findbusiness.aspx?type=advanced
 
Joined
7 Feb 2012
Messages
188
Reaction score
40
Location
Liverpool
Country
United Kingdom
i would ring ideal back and get them to fix this.
try to see were the hot dhw is going
is it going down the flow or return?try this when pipes are cold and run hot tap
is the boiler lighting up and staying on for how long?
does burner light stay solid?
 
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
thanx peter
i have a fernox f1 which i had cleaned an the fernox system cleaner an renewed inhibitor when i installed new radiator in the kitchen 8 months ago when the system was refilled there was dirt in the mains blocked filling loop had the mains disconnected an flushed before reconnecting to the boiler

the engineer said that ideal would recommend a PRV before they would even suggest flushing heat exhanger or replacing it

just want it left right so i'm keeping up with my warranty because excuses don't wash with me when they try to blame something else but the boiler

i'm not in a hard water area the mains pipes are plastic till 1st stop cock in the kitchen
 
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
i would ring ideal back and get them to fix this.
try to see were the hot dhw is going
is it going down the flow or return?try this when pipes are cold and run hot tap
is the boiler lighting up and staying on for how long?
does burner light stay solid?
definatly going down the right pipes
the boiler light lights up an stays lit till tap off
thats with the boiler a 58 degrees on the switch
with tap full open max temp i was getting was 44 deg after 5 mins running
but from tap off to just a quarter turn on tap 58 degree in a minute skin off lol
doesnt seem like it wants to go any higher unless tap nearly off
it used tobe other way round tap full open boiler firing right up boom instant hot water thats why i never had to touch the dial for a year an a half 55 was enough
 
Joined
5 Dec 2012
Messages
694
Reaction score
96
Location
Surrey
Country
United Kingdom
since it is still under warranty get them to come back and test it with a flow meter that will simulate a PRV which you don't need.
 
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
please tell me if i did this right
i set my boiler to 55 degrees turned tap on full boiler reached 39 degrees no more
while at that temp filled a 10ltr bucket just 50sec

i also set the dhw temp to lowest 40 deg which boiler reached perfect with the tap open full and it felt like it at the tap no problem an it had taken just 50 sec to fill 10ltrs

now with boiler set at 55 dhw turned tap to 1/4 turn reached 53 degrees then filled same bucket 10ltrs 1min 21secs an that same engineer told me too high water pressure WTF!!

so to me defs sounds like the boiler isn't stepping up that extra notch to heat the water unless you slow the flow down something def not right ??
 
Joined
5 Dec 2012
Messages
694
Reaction score
96
Location
Surrey
Country
United Kingdom
Now you can do the maths of converting temperature to litres/min Set water temp at about 45-50degC the boiler should do that at 12.5 litres/min all day. well long enough to fill a bath anyway. If it won't do that get him to sort it out.
 
Sponsored Links
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
i def ain't mathmatically minded lol
but i set the boiler to 45deg with tap full open it reach 42deg even if i move the dial up to 50 deg the boiler isn't going over 42 deg tap open full which up to now i never had a problem


i know when the tap full open the boiler kicks in while the water running as i turn the dhw temp switch up gradually you can here the boiler stepping up as you call for more heat but once you go past 55 deg on the dial it's at the limit
42-44 deg water temp seems tobe the limit while tap full open


i did cold water test in the kitchen it was 10ltrs 45secs

then did the same test in the bath 10ltrs 30secs but my hot water doesn't come out that fast

thanx for the help again
 
Joined
5 Dec 2012
Messages
694
Reaction score
96
Location
Surrey
Country
United Kingdom
The hot water is always slower than the cold tap due to resistance going through the boiler heating circuit. your boiler is only capable of heating the cold water it a rate of 12.5 litres /min The cold water coming into the house is less than 10degC plus 35deg rise in temp at 12.5 litres/min = max 45degC at 12.5litres/min at that temperature the 10 litre bucket should fill in 48 sec and the water should be 45degC any hotter at that rate is a bonus. That is why I don't like combi's. Normal temp of a hot water cylinder is 60degC
 
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
do you think what my boiler is doing is normal regardless of brand lol i said the C/H side perfect no problem this far
 
Joined
5 Dec 2012
Messages
694
Reaction score
96
Location
Surrey
Country
United Kingdom
If you can fill a 10litre bucket with hot water at 45degC in 48sec then the boiler is working ok and when the weather warms up a bit the water will get hotter, if the weather gets down to zero for a few daays the water will get colder at same flow rate. If you can make the water hotter by slowing the flow down then that is the best answer. The easiest way is to turn tap on fairly fast to fire the boiler and then slow it down maintaining boiler at full rate. And don't flush the toilet or have the washing machine or dish washer on since they will effect the water flow rate. If you have an outside tap that is the best place to test flow rate of water and I expect it is about 20litres/min or 1 bucket in 30sec
 
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
If you can fill a 10litre bucket with hot water at 45degC in 48sec then the boiler is working ok and when the weather warms up a bit the water will get hotter, if the weather gets down to zero for a few daays the water will get colder at same flow rate. If you can make the water hotter by slowing the flow down then that is the best answer. The easiest way is to turn tap on fairly fast to fire the boiler and then slow it down maintaining boiler at full rate. And don't flush the toilet or have the washing machine or dish washer on since they will effect the water flow rate. If you have an outside tap that is the best place to test flow rate of water and I expect it is about 20litres/min or 1 bucket in 30sec
outside tap 10ltrs 42sec
but thats one off them b&q clamp on fittings so restricted flow anyway

thanx again
 
Joined
5 Dec 2012
Messages
694
Reaction score
96
Location
Surrey
Country
United Kingdom
good cold water flow then, don't bother putting a PRV on supply, and if your hot water can fill the bucket in 48sec with hot water at 45degC since temp is a bit up at the moment, then boiler is working ok.
 
Joined
26 Apr 2011
Messages
31
Reaction score
0
Location
Londonderry
Country
United Kingdom
nothing is ever 100% accurate i got 10ltrs 45 degC 52sec =12ltrs every 1min 4secs hardly life changing

since i have have 5 yr warranty going to leave it till warmer weather if no change with it when cold feed in is that bit warmer then i will get on the ball to ideal

again peter thanks for your help :cool:
 
Sponsored Links
Top