What are these jumpered connectors on the outside of my Jandy Laars LT400N-L heater?

[ron_jeremy]

I'm having intermittent issues with my Jandy Laars LT400N-L heater. It always turns on but runs for a random amount of time before quiting -- each time throwing either a 'Pressure Switch" error or a "Hi Limit" error. I searched the forum and found this post so I decided to inspect the limit switches and noticed these connectors hanging on the outside of the heater with a jumper wire in each one. When I picked them up for a closer look the jumper wire fell out of one of the connectors and I'm not sure where to plug it back in.

Are these two connectors the limit switches?
If not, does anyone know what they are for?
Should I put the jumper back into the one connector? If yes, does it matter where it goes?

 

[Bperry]

I'm having intermittent issues with my Jandy Laars LT400N-L heater. It always turns on but runs for a random amount of time before quiting -- each time throwing either a 'Pressure Switch" error or a "Hi Limit" error. I searched the forum and found this post so I decided to inspect the limit switches and noticed these connectors hanging on the outside of the heater with a jumper wire in each one. When I picked them up for a closer look the jumper wire fell out of one of the connectors and I'm not sure where to plug it back in.

Are these two connectors the limit switches?
If not, does anyone know what they are for?
Should I put the jumper back into the one connector? If yes, does it matter where it goes?
View attachment 553936
View attachment 553937

Looks like someone bypassed something on the heater.

 

[swamprat69]

Those 2 receptacles are wired in series. Obviously the wire jumpered around both switches that the receptacles were plugged in to. From looking at the wiring diagram, there is a good chance that they are the high limit switches ( safeties that prevent the heater from overheating ). The heater should not be run with ANY safeties jumpered out of the circuit as it is not SAFE!

 

[1poolman1]

I'm having intermittent issues with my Jandy Laars LT400N-L heater. It always turns on but runs for a random amount of time before quiting -- each time throwing either a 'Pressure Switch" error or a "Hi Limit" error. I searched the forum and found this post so I decided to inspect the limit switches and noticed these connectors hanging on the outside of the heater with a jumper wire in each one. When I picked them up for a closer look the jumper wire fell out of one of the connectors and I'm not sure where to plug it back in.

Are these two connectors the limit switches?
If not, does anyone know what they are for?
Should I put the jumper back into the one connector? If yes, does it matter where it goes?
View attachment 553936
View attachment 553937

Those are where the two high-limit safeties are supposed to be. DO NOT use the heater without them.

High-Limit Switch Assembly

www.poolzoom.com

 

[ron_jeremy]

Thank you all for the help! I have no idea who jumpered the connectors or when it happened but I guess it's a good thing the heater is rarely used!

@1poolman1 I noticed the high-limit switch assembly you suggested is for LRZM heaters but mine is a LT heater. Are you sure it will work for my heater? The same website lists different parts for LT heaters as seen at the below link (parts 40, 41, and 42) that are collectively about three times more expsensive:

Jandy Laars LX/LT Heater Parts

Lastly, I'm not sure where these switches go. Do they go inside the black housing in the first pic I posted?

 

[ron_jeremy]

Update: I ordered new limit switches and the wiring harness. Considering the existing harness was just dangling outside the chassis I have no idea where to install the new limit switches.

Any ideas?

 

[1poolman1]

Update: I ordered new limit switches and the wiring harness. Considering the existing harness was just dangling outside the chassis I have no idea where to install the new limit switches.

Any ideas?

The switches fit into small cavities in the manifold. You also need the retainer plates to hold them in, part #R0336500, if they aren't there. Unfortunately, like most things for that heater, they are no longer made so may be difficult to find.

​

 

[ron_jeremy]

The switches fit into small cavities in the manifold. You also need the retainer plates to hold them in, part #R0336500, if they aren't there. Unfortunately, like most things for that heater, they are no longer made so may be difficult to find.

View attachment 554080​

Thank you so much for the help. Looking at the first pic I posted, is the manifold the big black plastic piece (at top of photo) that the pipes go into, or is it on the other side of that black plastic piece (inside the chassis)? I need to find out asap whether I need the retainer plates since we have guests coming in a week that are expecting a warm pool to enjoy

 

[ron_jeremy]

Ok I think I figured it out. The lower retainer plate is missing and the other was not even secured so I removed it and noticed there's some kind of rubber backing to it. Anyway, it's not looking good since these parts are not available anywhere

 

[1poolman1]

Ok I think I figured it out. The lower retainer plate is missing and the other was not even secured so I removed it and noticed there's some kind of rubber backing to it. Anyway, it's not looking good since these parts are not available anywhere

View attachment 554154

View attachment 554155

The rubber plug was designed to force the switch up against the brass insert in the bottom of those cavities. The brass is there to transfer heat to the switch. You can cut a piece of a "pool noodle" to fit tightly in the hole forcing the switch to the bottom and then use some screws and piece of wire to hold the assembly in place. Or, wedge the switch and foam tightly in place and cover the hole with silicone sealant to keep it in place. It works, I've done it. Those retainer-plate kits were almost impossible to get when they were being made.

 

[oldprophet]

Looks like someone bypassed something on the heater.

Those are the high limit sockets The green wire is a jumper wire. You are missing both high limit switches.

 

[ron_jeremy]

Thank you @1poolman1 and @oldprophet for the help. I noticed the lower well has room for two limit switches (as shown below) and the upper well has room for only one. I ordered 1 x 135F switch (for upper) and 1 x 150F switch (for lower) but was I supposed to buy 2 x 150F switches for lower well? It's weird to me that the lower well has room for two switches plus one switch in upper well but the wiring harness only has two plugs for switches.

 

[1poolman1]

Thank you @1poolman1 and @oldprophet for the help. I noticed the lower well has room for two limit switches (as shown below) and the upper well has room for only one. I ordered 1 x 135F switch (for upper) and 1 x 150F switch (for lower) but was I supposed to buy 2 x 150F switches for lower well? It's weird to me that the lower well has room for two switches plus one switch in upper well but the wiring harness only has two plugs for switches.

View attachment 554485

1 - 150, 1-135. Be sure it is up against the brass insert in the well.