ideal mini s24

[keltoyboy]

Had a strange one the other day....servicing one of these and customer tells me sometimes hard to start....but if he closes off the flow to upstairs rads fires up no problem.... tried to fire up it wouldn't and he shuts off water to upstairs and boiler fires straight away....
flow switch not making on micro switch but with increased water pressure when water is off upstairs it makes fine....
if switch was not making at all would think diaphram....but as it makes under more water pressure am thinking its heat xchanger getting clogged up......
Any ideas/ suggestions??

 

[southcoastboile]

does it work fine on hot water? is this a rebadged bisai 24s ? (newer style than the old 24s m96/24sm/c or woteva they call it)

 

[keltoyboy]

does it work fine on hot water? is this a rebadged bisai 24s ? (newer style than the old 24s m96/24sm/c or woteva they call it)

Its a system boiler southcoast.....not sure if its rebadged....its an oldie....bout 01 i think!!!

 

[Roger Welton]

They are as you say rebadged Biasi's I would start by pulling the flow diaghram to check condition and go from there.

 

[southcoastboile]

ok, I thought it was a combi. A partaily split diaphram may still activate flow swich, thats why combis work on hw when the htg is on, the extra pressure behind the diaphram activates the flow switch even if the diaphram is split.
Sounds like there is a partial blockage in the heating circuit then or the pump is running to slow. I would probably still change diaphram to start off with.

 

[southcoastboile]

They are as you say rebadged Biasi's I would start by pulling the flow diaghram to check condition and go from there.

yeah but isn't it a combi then?
ignore that im thinking of 24c i think

 

[keltoyboy]

yeah but isn't it a combi then?
ignore that im thinking of 24c i think

Spot on...24 c is the combi...the 24s is the system!

 

[southcoastboile]

Spot on...24 c is the combi...the 24s is the system!

ok well see if you can replace diaphram to start with and check for sludge behind it, the waterway behind the diaphram on the combi tends to block up so I always give that a clean while diaphram is out (I know the combi version quite well but cant picture the system in my head).
Failing that and the pump seems ok I would sugest a flush to the customer and rightly or wrongly I would bend the microswitch lever out slightly so it makes in the meantime. This is up to you and I am not saying its the correct thing to do, the oposite infact. Tell the customer this is a temporary meassure.
Also check for the obvious before hand such as flow/return valves fully open.

 

[keltoyboy]

ok well see if you can replace diaphram to start with and check for sludge behind it, the waterway behind the diaphram on the combi tends to block up so I always give that a clean while diaphram is out (I know the combi version quite well but cant picture the system in my head).
Failing that and the pump seems ok I would sugest a flush to the customer and rightly or wrongly I would bend the microswitch lever out slightly so it makes in the meantime. This is up to you and I am not saying its the correct thing to do, the oposite infact. Tell the customer this is a temporary meassure.
Also check for the obvious before hand such as flow/return valves fully open.

Ha ha!!!.funny you should say that southcoast......great minds think alike.... told them i thought heat xchanger was getting blocked and system could do with a flush....rads cold at bottom etc....and don't tell anyone but i bent metal in switch out ever so slightly...

 

[hot stuff]

Hi keltoyboy did you ever get to the bottom of this problem I'm sufferring the same problem.