Clicking Relay on an Old Bullfrog Hot Tub

[djemaine]

I have a 19 year old Bullfrog model 451 hot tub. The pump seal was leaking so I replaced the seal and motor bearings. After reinstalling the pump/motor and filling the tub, I powered it on. Pump/motor works fine, but one of the relays in the control box is clicking constantly. The clicking is very rhythmic, perfectly in time. Control box is a Balboa, model number DUM-BULF70-DCAH.

When I press a top-side control panel button, the clicking stops momentarily until the display changes, and then the clicking continues. When I unplug the top-side control panel wiring harness from the control box, the relay stops clicking. Clicking resumes when I plug the top-side control panel wiring harness back in.

One other thing to note: When the power is first turned on, the display shows "PR" to indicate that the pump is priming. The "PR" is soon replaced by "--F" indicating that the temp sensors are sensing the water temp. "--F" is supposed to go off after a minute, but it stays on much longer. I have not kept the tub powered on long enough to see the "--F" disappear, but it has been on in excess of 5 minutes.

[castletonia]

I would guess that you have a stuck button on the control panel since the clicking stops when it's unplugged. 

[Tman122]

Is it heating?

[djemaine]

Is it heating?

I'm not sure if it is heating. It never gets beyond the "--F" message before I power it down after 5 minutes or so

[djemaine]

I would guess that you have a stuck button on the control panel since the clicking stops when it's unplugged.

I took the control panel apart and checked out the buttons. Nothing obviously wrong with any buttons. So I hooked just the circuit board back up and turned on the tub. It behaved normally - no relay clicking. I then pushed the buttons using a piece of wood, and they all seemed to function normally. So I let it run, but after 5 minutes or so the relay started clicking again. Based on this test, I think you are correct that the problem is caused by the control panel.

[djemaine]

The saga goes on. Replaced the top side control panel - and the relay clicking stopped. Also replaced the heater while I was at it, since the old heater had a tiny leak around one of the temp sensors.

Filled the tub, turned it on, and it behaved normally for several hours - pump running fine, water coming out of jets, temp coming up. Then over the course of about 4-5 hours I had 3 occurrences of "Dr" or "Dry" messages, indicating a dry heater. Checked all of the usual culprits, found nothing wrong, and once again the tub started running normally. Then last night had 2 occurrences of "PR" messages.

This morning I kept a careful watch on the tub for about 20 minutes. In that time, it went thru 3 of the following cycles:

1. Message "24" - which normally only shows when tub is first powered on at the GFCI breaker
2. Message "PR" after a few seconds (priming)
3. After priming complete, message "--F" (trying to establish water temp)
4. After ~1 minute, temp shows as 102
5. Almost immediately cycle restarts and goes back to "24"

Could this be caused by a defective temp sensor on the new heater?

Or is the motherboard faulty?

Other ideas?

Thanks for your help