I think I have a problem coming up... - Page 2

SCVJeff · 11-21-2008, 03:58 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by troth:
Great pics Jeff!
I presume the relay came off the board with a little persuasion (it wasn't soldered on, was it?).
Do you think those were silver contacts? <span class="ev_code_BLUE">They appear to be silvered, except that which is now carbon.. . The relay is a board solder-on so those that are not comfortable with removing multi-pin components from plated-thru boards might not want to attack this. </span>

One good thing is that all the relays look the same, so it's good advice to buy one and keep a spare on hand. Could you get one from NAPA, or did you get it from HWH? <span class="ev_code_BLUE">Yes, all the white relays are the same SPDT 12V coil devices. These are not anything that a NAPA will have. I bought two through HWH. They were either $3 or $6ea. Don't remember. </span>

As to reason for failure, can you speculate about why it happened? Was the pump usually actuated when your coach engine was off, perhaps energizing the solenoid around 12vdc instead of 14 vdc from the alternator? (I've heard that lower voltage may be more damaging on some contact points). Your coach is pretty new, and I've not heard others complain about "losing a relay" on their HWH system. Perhaps it was just a defective manufacturer's part. <span class="ev_code_BLUE">As mentioned above I think some peoples assumption that a "delay" is normal, there is nothing on the logic board to force one. In this case the pump did come on, but it was either delayed (until the current could burn through the carbon), or thinking that multiple hits on the switch to get the pump on was caused by the switch. My bet is this relay since there is zero current across the switches.</span>

<span class="ev_code_BLUE"> With reference to the voltage; This relay drives the main pump solenoid only, so ALL this relay is driving is another relay coil. What you see here is back EMF caused by the main solenoid (sound familiar anyone?). These two solenoids are now on my list to install diode back EMF protection on after seeing this. </span>
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Sammie · 11-21-2008, 05:31 PM

SCVJeff, just wondering if in a pinch 12 volts could be applied to the pump itself with a jumper wire while activating the switch needed to retract a room slide or jack. You seem to be very smart when it comes to electronics, while I know just about enough to get by.

Thanks, Sammie

SCVJeff · 11-21-2008, 09:29 PM

(I thought about that too) Probably, to bypass this and one other relay, but there are other fluid valves involved and I don't know how they're controlled. Me thinks you would need an extra body to run the slide switch while you jump the coil. HWH doesn't want to release the schematic on that board..