Confused about heater bypass valve

[jacob_coulter]

What exactly is the purpose of this valve?

I'm not sure if something is wrong with my spa heater, but if I either open this valve all the way, or close it all the way, my heater goes into a "high limit" mode.

If I open it up about half way, I can get the heater to work, but it seems to be really slow about heating the water.

Can someone give me a "Dummies Guide" to how to effectively use this valve?

Thanks again

 

[JasonLion]

There are two distinct uses for a heater bypass, which are often plumbed slightly differently. One is to completely stop water from entering the heater, which requires that you are able to turn off both the input and the output. The other is used when the flow rate is higher than the heater can handle, which only requires a single valve. It sounds like you have the second kind. A photo would help us be certain which purpose your setup was designed for.

Assuming your system is meant to deal with a higher flow rate than the heater is happy with, you just put the valve in whatever half way position that makes the heater happy and leave it there.

 

[jacob_coulter]

The blue round valve that's labeled "heater bypass valve" The tan pump with the red shut off valve is the spa filter that runs through the heater.

Assuming I need to put it on a "medium" setting, what heats up the spa faster, more closed than open? Or vice versa?

 

[JasonLion]

Most heaters automatically compensate for the flow rate over a fairly wide range, so the change in efficiency is normally quite small. That said, higher flow rates, ie bypass closed, are more efficient.

You appear to have a simple bypass, where the heater is always wet, even when bypassed.

If you have the filter clean and close the valve, and then open it until the heater is happy plus just a little bit more that should be ideal. If you are not using the heater at all you can turn it off and open the bypass valve all the way to have a slightly more efficient plumbing system.

 

[jacob_coulter]

Most heaters automatically compensate for the flow rate over a fairly wide range, so the change in efficiency is normally quite small. That said, higher flow rates, ie bypass closed, are more efficient.

You appear to have a simple bypass, where the heater is always wet, even when bypassed.

If you have the filter clean and close the valve, and then open it until the heater is happy plus just a little bit more that should be ideal. If you are not using the heater at all you can turn it off and open the bypass valve all the way to have a slightly more efficient plumbing system.

Thanks for the response.

So hypothetically, the more I "closed" the bypass off (turning the valve clockwise) the quicker it would get the water hot (assuming I don't shut the heater down)