How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Phil Your Own Question
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 7914
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

We have a Ruud HRV 100 air exchanger. When the outside

Customer Question

We have a Ruud HRV 100 air exchanger. When the outside temperature gets in the teens or lower the defrost light flashes.
Water seems to be building up in the large core filter.
We have not noticed water discharging from the plastic line that runs from the exchanger to the drain.
Do you have any suggestions as to what we can do to get it working properly?
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, in weather below freezing, the incoming cold air freezes the moisture in the warm exhaust air... in order that ice does not build up there is a defrost cycle built into the unit, so that when frost is detected the unit goes into defrost mode. If the unit resumes working again after the defrost then that part of unit is operating normally.

Some water would be on the large core filter but should not be building up.

Can you use the paper clip icon at the top right of the tool bar to send me a few pictures of that, and the drain pan area taken from far enough away that I can see it in context?

We can go from there without a time limit.

Customer: replied 1 year ago.
I am at work now. Will touch base this evening. Thanks.
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** work, I am in until 9 pm west coast time

Customer: replied 1 year ago.
I sent a picture. Is it good enough for you to make any sense out of it.
There is no moisture in any of the filters at this time. It has been shut off for several days.
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 1 year ago.
I think I bumped the phone call by mistake. I sent a picture from our user manual that shows the light that flashes, that reflects that the defrosting cycle is malfunctioning.
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** the filters last changed, dirty filters will cause both the error codes and the icing. I see Nov 2013 on them... have they been kept clean since possibly.

Let me know about that.

Beyond this issue I need to see a bunch of flash photos of the insides of the filter/ heat exchange box with the filters removed, next time it produces these error codes.... I am putting no time limit on this for you, our software may show the question has timed out etc, ignore that and post when it fails again and with some very clear pictures of the insides of the filter heat exchange box.

We can go from there.

Customer: replied 1 year ago.
Sounds good. The nov 2013 is the purchase date of those filters. When the filters are clogged there is a different light that flashes on the control panel. We clean them at that time.
I will get those pictures of the inside of the box in awhile. I'm outside at the moment. Have a good evening.
Customer: replied 1 year ago.
Here are some more pictures.
Expert:  Phil replied 1 year ago.


we can go from there without a time limit until we get the system diagnosed.

Customer: replied 1 year ago.
Thanks Phil,
It will be a day or two before I can get back to you.
Have a good weekend.
Expert:  Phil replied 1 year ago.

That will work, just post your response even if the notice says 'timed out etc' I will be here and pick it up.