Jump to content

Marquis display says "HOt" but not hot


Recommended Posts

As title says, display says HOt but the water is not hot.  I have reset the breaker but still will not do anything.  Water temp is cold.  Main pump was replaced about 3 months ago and has been working fine until the other day (breaker was tripped).  This tub is 15+ years old so was happy the pump lasted that long (replaced with same brand).  When I flip the breaker on the display shows it going through the checklist and then ends on HOt and stays there.  And suggestions on how to correct this?

Link to comment
Share on other sites

I'm not a professional, but it sounds like a temperature sensor has failed. The control board thinks the water is too hot, so it won't kick on the heater.

If you have a multimeter, you can test the temperature sensor to see if it's reading correctly, but given the age of the tub it's likely the sensor has failed.  They are a common point of failure so they are easy/cheap to replace.  

 

I had one fail on my two year old Hotspring Highlife tub - luckily for me the tub was under warranty so the techs came out and replaced it free of charge.

Link to comment
Share on other sites

Does the pump ever turn on during the checklist? Have you tested the fuses. Note the start up "checklist" sequence and  post. Post photos of the circuit board and the schematic on the inside cover so we can see what you have and how it is configured.

Link to comment
Share on other sites

Pump does not turn on.  According to the manual, that code is for when the pump won't stop running. Temp sensor has never been replaced so I could see that as a potential issue (especially with the water in our district).  Normally to diagnose issues like this (how I found out it needed a new pump last year), I just start unplugging things to bypass the faulty circuit.  But my tub has a giant step that has to be lifted out of the way to gain access to the panel which is a 2 person job.  Will report back with what I find once I can get a hand to get access to the panel.

Link to comment
Share on other sites

Was finally able to get access inside the panel today.  Display sequence is:

  1. not sure what it says at first because my breaker is about 10 feet away so I will start with what I can see:
  2. 100
  3. 114
  4. 21
  5. 240
  6. HOt

All fuses test out fine.  Both temp sensors test at about 22K ohm.  Heater reads 10 ohm.  Only thing that looks odd in the box is one wire that is connecting 2 "relay" looking things is corroded and brittle.  See attachments of the board and schematics.  Open to input.

Photo May 11, 5 22 54 PM.jpg

Photo May 11, 5 31 15 PM.jpg

Link to comment
Share on other sites

Replaced the wire with one that is solid but it didn't change anything.  I should note that the wire looked like that a last year (picture on my phone from that time confirmed) when everything was working.  But it was corroded and has a few loose strands so replaced just to be safe.  I should also note that I unplugged both pumps for testing but still see the same results.

Link to comment
Share on other sites

So I decided to put the tub into test mode to see what happens.  It has 3 clicks inside the panel somewhere, then goes through the same start up on the display but now reads OHH.  After taking out of test mode it still says OHH (in place of HOt) even though the water temp is 75F.  I'm not afraid to replace some parts but not sure what the next step would be since the temp sensors and heater both seem to be showing about the right resistance (from what I have read but could be wrong).  So may replace them anyway?  Replace the relays?

Link to comment
Share on other sites

my guess is that there is a diode or something else on the board itself that has failed. You could remove the board and have a look on the back for darkened or burnt areas or broken pathways. Hold it up to the light and use a magnifying glass to inspect.

Link to comment
Share on other sites

20 hours ago, IsItFast said:

I'm not afraid to replace some parts but not sure what the next step would be since the temp sensors and heater both seem to be showing about the right resistance (from what I have read but could be wrong). 

If you used the word "about", then you are wrong. Sensors are precise, and a small discrepancy can cause errors (like hot, oh, ohh, sn, etc...) that shut down the heater or the entire spa. Your sensors should match within a few hundred ohms, which will be decimal points on your tester. So 12.3k (what your tester might read) is 12300 ohms. So if one sensor is 12.3, and the other 12.6, that's a bad sensor and an error on the display.

If the error occurs immediately after startup sequence, or sooner, it is likely a sensor or stuck relay. If it runs a few seconds or more after startup it is likely a flow issue, debris in the heater, or such.

The burnt wire on the heater relays does not bode well for the relays. 

  • Like 1
Link to comment
Share on other sites

I should specify, when I said "about" I was referring to what the resistance should be reading for the water temp.  Both temp sensors read exactly 29.5k so there is no variance between the two. 

Since I had my meter out, I decided to test the heater again.  And today, I can not get an accurate reading on it.  The terminals have a bit of rust on them, but even after cleaning, the reading jumps for a second then goes to 0 and won't move.  So maybe the heater is the culprit. 

Other than a couple of clicks, no pumps try to run after start up.  Unplugging the pumps and heater, I still hear these same "clicks" so I know it's not one of those items trying to come on but could be a relay.

Link to comment
Share on other sites

13 hours ago, CanadianSpaTech said:

Relays can be replaced cheaper than replacing the board.

True.  And after all my testing it appears the relay is remaining open as no power is going past the first one (I do have power coming into it since I repaired the bad spot). So new relays are on the way 

Link to comment
Share on other sites

  • 2 weeks later...
  • 2 weeks later...

Board fixed it.  Was a little nervous when "Pr" was on the display when I fired it up since normally it just kicks on instantly when the breaker is flipped.  But by the time I read that was code for priming mode (for 4 minutes), I went back out and it was running.  Hopefully it keeps on rocking at I'm about to build a new deck around it.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...