Help understanding a water level sensor

[Smellyglove]

I'm looking at adding a water level sensor in my HLT, to avoid the camco-elements getting fried in case something happens and the water level drops too much so they will be exposed in air.

This is what I've found so far. If it does what I think it does I'll shoot them a mail asking if it's 304 or 316.

http://www.ebay.com/itm/CR-Horizont...548?pt=LH_DefaultDomain_0&hash=item1c3a0f1e0c

I basically want it to shut off the pump connected to the HLT. Do I need anything else than this? A control unit or something similar?

*Edit: Do I understand it correctly if this should be in-line with the pump circuit. If I mount it so the floater drops when the water level doesn't keep it up anymore, the circuit is will break, meaning the pump will not get any power?

 

[BrewCrewKevin]

I believe so (although there's not much info on it.) I'm no expert, but I would agree with your assumptions.

It has 2 pigtails coming off of it, so it looks like you would put in in line with your Positive only. Neutral/Ground should go straight to your pump yet. So if this is tripped, it should basically open your positive wire. Voltage is really the Difference between the positive and neutral, so if positive is shut off, power should be shut off to the pump.

 

[Smellyglove]

I believe so (although there's not much info on it.) I'm no expert, but I would agree with your assumptions.

It has 2 pigtails coming off of it, so it looks like you would put in in line with your Positive only. Neutral/Ground should go straight to your element yet. So if this is tripped, it should basically open your positive wire. Voltage is really the Difference between the positive and neutral, so if positive is shut off, power should be shut off to the element.

Does it matter which line I connect it to? If you remove one of the wires then the circuit is broken, or am I mistaken?

 

[BrewCrewKevin]

Edit: Yes, you may be right there. Typically in electrical diagrams, it's the positive though.

Here is one example of one from PJ's diagram. Positive will be in-line with the switch. Neutral and Ground are still wired to the outlet (which would be where your element is plugged in).

 

[thefost]

I'm not sure that will work. The contact rating is only 50W, so might want to pick a different switch unless the pump you are using is very low power.

 

[VVbrewery]

I've been looking at doing the same with my HLT but I was going to put the float switch inline with the PID output to the relay controlling the element. When the water level drops the element can't be energized and burn up. That way it is protected if the water level drops because of a leak, leaving a valve open or other "operator error". Like turning it on forgetting that you hadn't put water in it yet. Not that I've done that.

 

[Smellyglove]

I've been looking at doing the same with my HLT but I was going to put the float switch inline with the PID output to the relay controlling the element. When the water level drops the element can't be energized and burn up. That way it is protected if the water level drops because of a leak, leaving a valve open or other "operator error". Like turning it on forgetting that you hadn't put water in it yet. Not that I've done that.

That was my initial thought and would be the best way of installing the sensor.

But I have to run two heating elements in my HLT, since there's not enough amperage in my wall socket to run them both from one socket or one bigger element. Besides, the sensor I liked to can't be installed inline with the heating element as it can't deal with the wattage. You'd have to find another sensor with a higher effect-rating.

Anyhow. I'll be getting another HLT (I use cheapo plasic ones food graded made for dog food) where I will re-drill the holes and install the valve above the heating elements, so the HLT can't be drained enough so the elements will be exposed. Then the only possibility things might go wrong is if I forget adding water before I turn the elements on or the bushhng should suddenly start to leak.

I don't know if It's bad practice (taste/bacteria-wise) to just have enough water in the HLT to cover the elements at all times. I will add a sight glass where 0 volume is at the same height as the valve, so the water under this point will never be drained and will just be there in case of stupidity should strike my brain.

 

[VVbrewery]

Well I can think of two ways to make it fail safe, well three with your method. Have the float switch control a small relay that disconnects the signal to the 2 SSRs or have a solenoid valve on the outlet of the tank that shuts so no more water can drain out when that level is reached. I don't think the latter idea is very practical. Your idea is simple. Simple is good.

I don't know about the critter/taste issue but I do know if I leave water in my HLT for some time the base of the element starts to rust. I don't know if it's a cheapo element or what but I've had to clean flakes of rust out of the bottom so I make sure to drain it completely.
Maybe just add a drain valve?

 

[Smellyglove]

Well I can think of two ways to make it fail safe, well three with your method. Have the float switch control a small relay that disconnects the signal to the 2 SSRs or have a solenoid valve on the outlet of the tank that shuts so no more water can drain out when that level is reached. I don't think the latter idea is very practical. Your idea is simple. Simple is good.

I don't know about the critter/taste issue but I do know if I leave water in my HLT for some time the base of the element starts to rust. I don't know if it's a cheapo element or what but I've had to clean flakes of rust out of the bottom so I make sure to drain it completely.
Maybe just add a drain valve?

I'm clearly thinking just inside a very tiny box. I thought I'd have to wire it inline with the PID, just shutting off the one element being controlled by a PID/SSR, instead of making it inline with two SSR's.

I'm only having one SSR & PID controlling the HLT. I will have to switch the other element off manually and not use it for the rest of the brew session because of power-limitations in my basement.The PID-controlled element is to fine-tune the temperature and keeping it there after the non-PID-element has helped the PID-controlled one getting the strike water up to temp..

That would mean I'd need to get another SSR, from china (I live in norway, to keep costs down I order all my toys from china). I've been thinking and ordering stuff for so long now that another month of waiting for a piece from china would just make me go crazy.

 

[VVbrewery]

Ok, I think I know what you're doing. If you're going to control the one element manually or have them both on one SSR then all you need to do put the float switch inline between the PID and SSR. Water level drops, no signal to the SSR, no power to element, one happy brewer.