Northstar heater problem - flow switch?

[outatime]

Hi Guys

Hope you can help me out here, so I installed a North-star heater into my Ram several months ago, used it maybe a dozen times on a few jobs but then just before the holidays I did quite a long tile job and the heater wouldn't shut off and started to give me too much pressure in the line that I couldn't get the wand trigger to open unless I turned everything off and let the pressure down slowly.

The heater gets to temp and the burner shuts off but the on demand heating won't work, It used to fire up when I pulled the trigger and then stop when I let go now it just stays on till the water gets to temp then shuts off so I am thinking the thermostat is working...it was new a few months ago so I am thinking it just leaves me with the flow switch which again was new a few months ago. I bought the General Pump flow switch as recommend on here but surprised it would die so fast. Do these things clog up easily? I would have fed water from my extractor to the heaters flow switch so maybe something is blocking it, opened it up but didn't see anything.

Hope someone can help please

Many thanks

Stuart

 

[SRD]

Sounds like the flow switch is bad or has some trash stuck in it, ive always used pressure switches instead of flow switches on my burner builds way more reliable in my opinion, if it was me and the flow switch was bad id replace it with a pressure switch

 

[Bob Savage]

This flow switch will last a very long time (years). I have one on each of my 2 LP heaters with no trouble at all. You would need to plug one of the holes on the switch with 3/8" brass plug.

It will even activate with household water pressure when low PSI cleaning.

 

[PistolPete]

I use suttner st-5 flow switch
https://www.kleen-ritecorp.com/p-18943-suttner-st5-vertical-mount-flow-switch-43801-psi.aspx

 

[PistolPete]

Definitely your flow switch BTW

 

[Bob Savage]

I use the ST-6 because it will mount vertical or horizontal, whereas my setup is plumbed for horizontal.

 

[PistolPete]

I use the ST-6 because it will mount vertical or horizontal, whereas my setup is plumbed for horizontal.

Yup, either one works depending on installation set-up

 

[outatime]

Thanks guys, ordered a ST6 just to be on the safe side, should be with me soon.

 

[PistolPete]

Thanks guys, ordered a ST6 just to be on the safe side, should be with me soon.

Let us know if this solves the issue, thanks

 

[outatime]

Thanks again guys, question, I add a rinse mix to my extractor water tank , think it Rob's alkaline rinse, would this damage a flow switch over time, it seemed fine before that?

 

[Bob Savage]

No, because I meter in chemical before the flow switch and it has had no adverse effects.

 

[outatime]

Hi guys, new flow switch in place and it worked perfectly, thank you.

But I do have concerns about the chemical rinse I add it to the fresh water tank, how can I add them so it doesn't cause any damage to the flow switch? Also will it cause any issues with my northstar burner long term? Thanks again

 

[Bob Savage]

It will not hurt your Northstar heater. I use a 240,000 BTU propane heater in both my slide-in and my ETM, and these heaters have a black pipe heavy duty coil just like the Northstar. I alternate between an alkaline cleaning agent and an acid rinse metered thru the heaters to keep the inside of the coils "seasoned", and occasionally run a vinegar mix thru the system.