Hot water not available when very cold

Hi All,
I have a on-demand gas hot water service and have found that
when its quite cold in the mornings or late at night, i cant get any
hot water. If i wait until it warms up a little, hot water flows
through fine.

I have looked at the unit, and it is successfully sparking when hot
water is requested, but the flame never lights - my guess (and it is a
wild guess) is that the thin gas pipe for lighting the flame has got
blocked by some moisture which has frozen when its cold and clears
when it warms up a little.


Anyhoo - anyone got any suggestions on what i can do to allieviate
this issue? As you can imagine, not having a shower before work isnt
too nice.


Thanks for any help.

Is the gas turned on, can you smell gas when the water is running?

yep gas is on, and no, cannot smell gas either when its functioning or not functioning.

If you can't smell gas then it must be blocked somewhere maybe the jets as you said, You need a gas person (plumber) to look at it for you,.

had a plumber look at it, couldnt find an issue (hence my post here) - and the fact that it only "blocks" when cold, would seem to suggest that its related to the weather, not a more permanent block...

was hoping someone else had run into something similar.

slow reply - but just to round out... i ended up just replacing the hot water service... for $800 it was cheaper to replace than to keep on getting plumbers out with no progress!

Hi
Most gas hot water systems except for storage work on flow rates. I would suggest that you turn on your hot water tap only. Once the water comes through then add cold water. If you turn the cold tap on first than add hot water, sometimes the heater will not fire up the burners.
Most heaters require about 6/min to fire up.

If this doesnt work, it may be the power pack has gone on your heater especially if it is Bosch unit with no power cord attached to it

Regards
Shane