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 Rick Your Own Question
Rick, Construction Supervisor
Category: Plumbing
Satisfied Customers: 21363
Experience:  Licensed Master plumber with 40+ yrs. experience.
Type Your Plumbing Question Here...
Rick is online now
A new question is answered every 9 seconds

My Rheem professional water heater light is flashing blue

Customer Question

My Rheem professional water heater light is flashing blue slow 3 times and then pauses. Do you know what that means?
JA: How long has this been going on? And how severe is the problem?
Customer: No hot water, just started.
JA: Do you plan on doing the work yourself?
Customer: If it's simple to fix.
JA: Anything else we should know to help you best?
Customer: no.
Submitted: 12 months ago.
Category: Plumbing
Expert:  Rick replied 12 months ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

3 flashes is a draft pressure switch open error. This switch must close proving there is adequate draft before the burner will fire up. One possible cause is a blocked exhaust vent.

Customer: replied 12 months ago.
How do I fix this problem?
Expert:  Rick replied 12 months ago.

You need to check the exhaust vent for blockages. Another possibility is that the small diameter vacuum tubing connected to the switch (on top of the heater) is kinked, disconnected or has water in it (should be dry). Beyond that assuming the exhaust fan is working, replacing the switch is the next step.

Expert:  Rick replied 12 months ago.

The pressure switch is a sort of disk shaped object (see attached pic for typical)

Customer: replied 12 months ago.
No blockages on what I beleive is the exhaust vent on top of the water heater. I'm assuming it's the black vent on top of the heater. Is that correct, where is the switch. all I see on top is a giant black large vent attachement and the hot and cold water pipes.
Expert:  Rick replied 12 months ago.

You seem to be describing the exhaust fan assembly. The vent is the pipe connected to it. You need to start where that pipe terminates outdoors. I gave you a pictures of a typical pressure switch and it has a small diameter tubing connected to it. It's on top of the heater attached to the fan assembly.

Customer: replied 12 months ago.
Do you have a clearer picture of the switch and where would it be located. I see the fan assembly and the tube that is pressed up against it and leads outside the house. I can't find the switch. Is it embedded inside the fan assembly below the piping attached to it leading outside. If I find it is it easy to replace?
Customer: replied 12 months ago.
If so, can you provide the steps to replace it and where to find one?
Customer: replied 12 months ago.
Should the part be under warranty?
Expert:  Rick replied 12 months ago.

The only place you can buy a switch is a plumbing supply house hat sells Rheem and they usually won't sell to an unlicensed person. Your best chance is to check out the other possibilities I mentioned before. I need the model number of your unit

Customer: replied 12 months ago.
PROG50-42N RH67 PV
Customer: replied 12 months ago.
The tubing is PVC pipe so no kinking and it's nor blocked and is dry.
Customer: replied 12 months ago.
Must be the switch
Customer: replied 12 months ago.
Could it be that the PVC piping got wet from a big storm and damaged the switch. Obviously now everything is dry. However, this would leave the switch damaged.
Expert:  Rick replied 12 months ago.

Have you checked where the vent terminates outdoors? No the switch tubing is not PVC the vent is PVC.

Customer: replied 12 months ago.
it looks fine and unblocked.
Customer: replied 12 months ago.
the switch is connected to the other small diameter tubing on the end?
Customer: replied 12 months ago.
the PVC vent pipe is not blocked.
Customer: replied 12 months ago.
With that said it's probably the switch as I suspected.
Expert:  Rick replied 12 months ago.

Looks like there is an access panel you have to remove to get to the switch on this model. If the tubing to the switch isn't kinked or full of water then it could be the switch. If the unit is less than 6 years old it may be under warranty.