Alternative to an Amtrol smart board?

Skunkdynamite

Hello everyone, sorry if this is too far outside the box.

I have an Amtrol WH71L with a malfunctioning smartboard. Boiler operates normally for the heat zones, but doesn't fire when the HW calls. I currently have the zone valve open manually and am running the baseboard periodically to meet demand.

I've seen there is an issue with these units so rather than buy the next POS to let me down on a Friday night can I use an Inkbird PID controller to operate the system?

I used one of these to convert an old toaster oven into a tempering oven for making knives. Seems like it serves the same purpose, switching on off/ high low limits and temperature set.

Sorry in advance if this is wacky, but it seems like it's worth it considering the price of the Amtrol units.

Jamie Hall

And how do you know positively that it is the smartboard and not one of the inputs to it? Have you checked every input device for correct operation and every connector, wire, power supply and ground for integrity?

Doesn't sound like it.

109A_5

Hello Skunkdynamite,

I'm relatively sure an off the shelf temperature controller could be made to work. The Amtrol smartboard is just a custom temperature control for a specific application.

With an off the shelf temperature controller you have to make sure the output contacts are suitable for the loads (voltage, current, isolation, amount of, safety lockouts), the temperature controller is programmed correctly, the temperature sensing device (thermocouple or the like) can be placed in a good place.

BTW off the shelf temperature controllers fail too.

SuperTech

I prefer to use analog control for the boilermate. Why not just install one of those and use it to control the zone valve?

HVACNUT

A simple L4006A will work. Just the switching. Cap the Common.

Skunkdynamite

I should have added that I'm broke as the reason for seeking alternative controls. Besides working part time all year, I just spent whatever I had left because I hit a deer and totaled my car. When it rains it pours!

I'm just analyzing the function of this unit and it seems like temp in, power and switching are basic functions, not proprietary to Amtrol. The boiler does all the work and functions normally in every other zone. This is a $400 vs. $40 question really.

What lead up to this, is the hot water was getting hotter than my settings, and then there was no hot water at all. Taking the board out shows this magical looking burn spot underneath microprocessor, but I have no way to test the circuit board itself. This is the original unit since the house was built in 01, so I thought it was the culprit.

What should the resistance value of the temperature sensor on the tank be at 145°? Out of the heated tank it was 9.4 ohms. Running it under cold water raises the resistance, heat lowered it. The sensor itself seems very responsive to temperature.

clammy

It has work for me more then a few times ,that's if you are comfortable do a little control wiring . Use a ranco Electronic temperature control .cheaper setable differential and lockable keypad available in 208/110 or 24 volt with a sensing probe. I use them in place of just about every mech aquastat it s a wiser choice being there very accurate and in my eye highly dependable i don't think i ve had one fail that i have installed excellent track record . I ve used them a few times just on amtrol tanks being there on the truck and last time it was less then 1/2 the price for that stupid oem board ,if a indirect that i am installing has a mech aquastat its gone and a etc is put in its place there no thought about it and when there digital fails a etc is installed plain simple .

peace and good luck clammy

109A_5

Hello Skunkdynamite,

Can you take a photo of the component side of the board ? The microprocessor should not be getting that hot to discolor the circuit board.

9.4 Ohms seems kind of low for a thermistor, too high for a thermocouple, and also too low for most RTD type sensors. However it may be some special sensor the OEM conjured up.

Skunkdynamite

After messing with this all day, probing wires, Checking connections, contacts, temperature sensors, swapping zone valves I ended up putting a new wire from the Amtrol unit to the zone valve and it lit right up 🤦 I can visibly inspect the whole wire and see nothing wrong with it.

I feel like the dad in a Christmas story... There's definitely a tapestry of obscenities hanging over my house today 😂

Jamie Hall

Glad you found it. I do more cars than boilers, so perhaps I'm a bit paranoid — but I've found that 9 times out of 10 the problem isn't the board or module or sensor — it's a bad connection (plugs and sockets, grounds, what have you) or a bad wire…

109A_5

Hello Skunkdynamite,

The circuit board overheating is apparently due to a poor design issue, insufficient heatsinking of what appears to be a surface mount three legged voltage regulator, not the eight legged I.C.

I'm glad it is presently working for you. Sadly with you not being able to confirm the bad wire with an Ohmmeter or a Voltmeter when the wire was actually in a live circuit, I fear it is an intermittent issue that has been temporally stimulated into proper operation. Sometimes agitating an intermittent issue just fixes it for a short time.

Even though the picture of the solder joint side of the circuit board was a bit blurry there were a few solder joints that looked suspicious to me. Cracked or otherwise poor solder joints will cause all sorts of erratic issues. Very common to see bad solder joints at the relays and transformers and components that run at elevated temperatures.

If it fails again inspect that board carefully, use a magnifying glass if necessary. Reflowing solder joints is not hard or expensive.