Breakdowns in cold weather

[back2space]

According to the BBC news, the UK is in the midst of a big freeze!!! We have snow on the ground in many places and temperatures are rather chilly!

Im wondering whats the most common faults/breakdowns in this sort of weather? Units not heating properly, that sort of thing.

Would be good to discuss common faults etc.

[superswill]

over condensing ive find on a few systems,so a trip to the wholesalers it is was to stock up on fan speed controllers

[Brian_UK]

(Slightly ) I think us Brits must be a soft lot really.

One of our Mods was just telling us about the snows beginning to fall in the US of A and wondering whether they would top last years total of 110 inches

Makes our little snow falls seem a bit weak doesn't it ??

[coolments]

Hi Sline
As most of our business is comfort cooling a lot of our calls have been to customers who havent had maintence done or cancelled earlier in the year and units not heating efficiently mainly due to blocked filters & also people who depend on the AC for heat but leave it off over night and the units are struggling to warm the room up in the morning, we advise them to instead of turning it off at night just turn it down so the rooms dont get to cold over night.
I have noticed though last month a sudden increase of maintenance contracts being accepted and a decrease in sales of new kit, must be the credit crunch and people wanting to keep what they got running as best as it will. what about you, what are you finding.

And yeah Brian why dont we get some serious snow anymore instead of the over night stuff that turns to slush next day, i want to take the kids sledging.

[back2space]

totally agree its pathetic we get headlines about artic chill and its only how winter should be! The snow was not that bad yet were ill prepared and britain grinds to a halt!

I rely on ac for heat. I started by turning it off at night but was taking too long and using too much electric... I'm on a coin meter... That i've started lowering set point to 18c when i know i'm gonna be in next day so as the house doesn't get too cold its got poor insulation so can drop to 13c inside easily. Would you drop it lower or take it higher on a night?

[HeathT]

Have found an increase in complaints from customers saying a/c systems taking too long to warm building through. Mainly found that units are starting in defrost cycle cos of the low ambient. Mostly mitsi vrf, defrost cycle starts at -5 celsius and checks the termistor after 20 minutes and if it is not at +10 celsius it will continue defrost cycle. Not alot you can do really apart from setting the central controller to start up earlier so as to start the whole cycle.

[back2space]

How long should an ac unit take to bring the rooms upto a reasonable set point of 21/22? WOuld you say a couple of hours?

[Brian_UK]

How long should an ac unit take to bring the rooms upto a reasonable set point of 21/22? Would you say a couple of hours?

That is unfortunately an opened ended question with no sound answer.

What is/are ... for starters

The start temperature
the unit size
the heat load
the discharge air temperature

[back2space]

On average though for a properly sized system that is working correctly.

For instance a central heating system takes a couple of hours before its started to reach near comfortable temps.

[HeathT]

it all depends on the ambient temp outdoors. like I say with low ambient have found that systems are starting in defrost cycle hence taking longer to heat up.

[coolments]

Experimenting with start times is probably the best option for you I think.

If properly sized air temp should rise quicker with AC as the air is forced around and central heating it is not, and should reach temp I would say in at least half an hour but the room would have cold feel until all the walls and room contents absorbed the heat also.

For instance on the reverse foot if your room was warm then you opened the window in winter for say 2mins and let cold air in the air temp would drop realy quick, as soon as you shut the window the room would recover temp quickly as all the walls and room contents are warm.

As said its an open question, all depends on how cold the room is to start with, how good your room insulation is, outdoor temps etc