LWCO.on water boilers?

David Sutton_5

What kind of lwco are you useing and why???what works better and what relieabilty are you having?
i Thank you all very much for your imput on this....David

Jack Ennis Martin

lwco for boilers

David
You cannot go wrong with Macdonnell anything. Be it 67 - 57- 150 -47 what ever you want to do safely ;Macdonnell can sell you the correct item. and If you ask for imformation ,they will give you all the help possible. The use for lwco outs on a water heating system comes in if there is a chance the system somehow looses the water charge and can run on a dry boiler. This is serious, especially for hot water systems having the boiler in an elevated installation ,such as a penthouse installation. The dumping of water in this kind of installation is usually rapid and has to be sensed immmediately. Hope it helped and all the best in your future installations.
Jack Ennis Martin

Dave_61

how about in this situation?

How about a boiler that's in the basement? Mine has a flow switch in the primary loop which will shut off the boiler if there is low/no flow.
In that situation, do I need a LWCO?

Unknown

for a water boiler

use a McDonald Miller RB122 (120V) or a RP24 (24V). Both screw directly into a 3/4 female adapter.

http://www.mcdonnellmiller.com/prod/products.asp

commerical water use a RP120 (120V)

the 67, 57, 150 and 47 are for steam.

Very few inspectors or manufactures will accept a flow switch as a LWCO.

regards,

wheels

Kal Row

i use and MD RB211...

i mount it high in the boiler room above the level of the pumps to protect them also

MAKE SURE - you put a float type auto air vent above it so that it will drop out if the water drops in the system

i use the a relay off it, to cut the ac to the boilers and the pumps - but leave the power to the controls and thermostats alive, so they dont loose their progamming

i have tha ac power busses split anyway, cause in this day in age with all the electronics - you need to put a computer UninterupteblePowerSupply on them to keep them alive and protect them from surges - especially if you live in an overhead powerline area - so i seperate the light electronics load from the heavy magnetic pump load - and put the ups on the electronics - of course the LWCO realy also has to cut the heat demand to the boiler so it stays at idle when on UPS since the pumps are not avail

see upper right of attached PDF

David Sutton_5

i'd say yes

all boilers should have one installed, in the event the boiler was to loose its water your boiler will not dry fire and destroy its self, i just had a 9 section boiler have both its brand new controls fail and baked the boiler cracked the rear section and melted all the seals, this was a very costly fix....David

Dave_61

lwco and flow switch?

Can I just change out the flow switch for an lwco on my boiler? What would stop the boiler from overheating if my main circulating pump died, but the system was still full of water? Do I still need the flow switch?
My house was built in 2001 in CT. Was it not to code at that time to be without a LWCO?

Unknown

manufacture required?

Dave,

Most of the time you will not find a flow switch on a large mass cast iron boiler. Notably a flow switch IS installed on a low mass boiler where the input flame will boil the water and/or harm the boiler if flow is not present prior to fuel ignition.

You probably should not "just replace" the flow switch with a LWCO.

What make boiler is it?

Steve

Kal Row

absabluminlutly not!!! ...

i costs real money to put in a flow switch - they would not do it if the heat exchanger did not need the protection,

Dave_61

low mass Lochinvar

We have a low mass Lochinvar EBN300 boiler. The flow switch is in the primary loop.
Do we also need to add LWCO? Where would that normally go in thepiping scheme? Should it have been installed from the beginning in 2001? (per code)?

Kal Row

if you have pumps at a highter level..

then you need a LWCO above it like my diagram in entry#5 in this thread - or another WFS inline with additional pumps

water cooled pumps have ceramic bearings, and only die if run DRY or get embedded with debris

the best WFS is the electronic type (using an rf or ultrasonic field), that can sense too many bubbles in the flow which could limits the heat transfer capability of the fluid and can damage the heat exchanger, that’s why pool heater use a pressure sw for good flow sensing – as the copper Heat eXchangers cant take much of a beating – and they will cut out on too much pressure (ie clogged pool filter) or to little pressure (ie inlet water restriction or air) – but that make for lots of nuisance service calls – which is ok cause the pool people like to have rich folks dependant on then – but would never fly on a heating system

Todd_9

? LWCO ON STEAM

I know its a good idea to use two lwco on a steam boiler, but is it a code? I like to use the probe type because most homeowners won't flush float style often enough. Someone was telling me that you would need a float and a probe style but I'm not sure where this is spelled out.

Unknown

both are a must

Lochinvar boiler comes with a flow switch because you HAVE TO USE IT! Low mass copper fin tube, fire it without flow and you will void all warranties and damage the boiler. Hence the reason for the built in flow switch.

You can also order it with a LWCO. Because not all codes require LWCO it is an option. It is used IN ADDITION TO the flow switch.

Looks like you are installing both. Leaset expensive LWCO is the MM RB122.

Steve

Dave_61

code question

Would this be a code issue in 200-2001 that my syatem did not have one of these LWCO's installed (though it did have the flow switch for my boiler)?

Dave_61

wiring LWCO

Steve,
Can this LWCO be wired into the same exact terminal spot on my boiler as my flow switch? So that when either one trips, the boiler doesn't run?

Unknown

wiring diagram

Dave,

Simple answer is NO.

More complete answer attached.

Steve

Robert O'Connor_7

Todd (@)?LWCO.com

Depends on where you live (which state) and which code(s) they have adopted. If were talking a small residential steamer in a state that uses the International Mechanical Code, then only one is required. When you get into light commercial and up, then more than one is required (goes by boiler HP/BTU/LBs per hour)..Additional limits are also required typically with manual resets.

Robert O'Connor/NJ

Kal Row

....

if you put it in the burner's limit circuit - is will just cut the burner - what you really want, is to cut the boiler's pump also

better would be to cut the ac to the boiler, if your boiler wont loose it's settings

i used an unusual solution in the attached pdf - of switching the neutral on low water cut out so that i could leave the tekmar powered and sill have it's pump drive effectively cut out off

Paul Mitchell_2

LWCO

Using the M&M RB-122...It is line voltage and we use it on gas and oil. So far...very reliable. Although one supplier gave me Taco's version and it seemed very good also. We tend to like to break the line voltage instead of the low.

Scott Kneeland

lwco

I have been using lwco on hot water boilers for almost 5 years and use a Hydrolever sv170 and have not had a failure or problem.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Joe Mattiello

Try a Taco LWCO

Attached is catalog information for the Taco LWCO, available in 120v, or 24v. These switches have drycontacts so you can use them anyway, to meet your system requirements.

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Dave_61

another wiring question

Steve,
Here is another question unrelated to the LWCO. I would like to add an outdoor sensor so that the second stage of the burner only comes on when the outdoor temp is below a certain level (I have a 2 stage burner). Is it possible to cut one of the wires to the second stage gas valve and wire it through an outdoor sensor that essentially acts as an on/off switch (usually off but turns on when temp is below certain point)?
Where could I get one of these sensors (brand, etc)? Thanks.
Dave

Unknown

outdoor reset

Dave,

It is a bit more then just a sensor. Actually it is a whole series of parts, but is possible to do.

It actually is offered as an option from Lochinvar.

Steve

Dave_61

Does Taco have outdoor reset I could install?

I have a Taco zone control panel with 4 zones and another single zone control realy (we have a total of 5 zones.
Each of these relays is then wired to its own 00 circulator (no zone valves).
Is there an outdoor rest I could buy and install myself in this situation without a ton of expense?...the Lochinvar one seems like overkill. Would that be Taco's PC700?How would that operate? I'm not looking to cahnge my water temp but to just keep the second stage burner off in warmer weather.

Kal Row

pls do not mess with the burner circuit, without....

using a factory approved system - unless you have serious knowlege and experiance and test equipment -

should it fail and blow - your insurance can claim arson - they have, and won, many times, they have more lawyers than you can shake a gross of sticks at!!!

dont mean to rain on you party, but a healthy dose of "chicken" is called for here

you can use a taco variable speed pump with outdoor sensor and you boiler will adjust acrordingly - paruse their site - www.taco-hvac.com - and also tekmar's site www.tekmarcontrols.com

Unknown

Simply put... NO

Dave,

IN order to maintain warranty you must maintain the flow properly through the heat exchanger (flow switch) and if you want to vary the nurner you have to use the lochinar supplied parts and install them as per lochinvar.

If you want the correct parts your supplier will also need our serial number so that Lochinvar can recognize your existing controls.

Regards,

Steve

Joe Mattiello

Taco outdoor reset pc700-2

The PC 700-2 is an outdoor reset that simply plugs into the Taco zone control panel SR504-EXP using a modular plug to facilitate the wiring. Hopefully, you have the EXP version of the SR board. Using outdoor reset is a great way to save energy, if you have a condensing boiler. If it’s a non condensing boiler with a minimum operating temperature of 140 degrees typically, the saving are less. Something to consider. For your reference I have attached the instruction sheet for the pc-702-2

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Unknown

Primary/Secondary?

Dave,

I do hope with the low mass boiler you do not have the boiler piped so that the zone circs are what is moving the water through the boiler.

As long as it is primary/secondary, then the TACO outdoor reset will give yur system a lower design temp without doing any harm to the boiler. MAKE SURE TO MAINTAIN THE GPM through the boiler or you will do damage to the heat exchanger.

Steve

Dave_61

We have SR-504-1

Joe,
Unfortunately, we do not have the -EXP but the 504-1 with a 501-1 piggybacked on.. What would be a ballpark retail price for the 506-EXP? The boiler is noncondensing and has a 2 stage gas valve so I was trying to find something that in warm weather would only allow one valve to open and in colder weather to have both stages open. Would the 702 be a better fit?

Dave_61

We do have primary secondary

Steve,
We do have a primary/secondary setup with a primary pump for the boiler circuit (Taco 0012). And then 5 007's on a supply manifold f(1 for each zone).
We had ALOT of problems with noise and flashing to steam when the boiler was first installed because our installer had never put in one of these low mass boilers before (that was in 2001).
What would we be looking at as far as damage if it had overheated due to his mispiping? It was a problem with noise and flashing etc for about 6 months before he got it semi-straightened out.
We are actually having someone come to repipe the primary loop this spring so it is all done correctly (our original installer insists nothing is wrong, but our main pump tends to seize each winter).
I could send you a digital picture of the setup if you want a good laugh.
Dave Stroman (on this board)was instrumental in looking at my system and seeing what needed to be changed in order to make it work properly.

Unknown

Heat Exchanger

Dave,

Actually there may be no damage. I've seen incorrectly piped boilers last many years with no damage. I've also seen them last two weeks before severe damage.

You can actually take a look at the copper heat exchanger. The tubes should be parallel and are on the same plane, not bowed up and down. If it is warped it may need to be replaced. Have a technician look at it or a representative from Lochinvar (they have field sales guys trained to do this).

Then look between the fins and make sure there is no build up of dirt and/or green goo from the condensing. If there is it will need to be cleaned.

Looking at all of this I still feel your best bet on the outdoor reset is with the Lochinvar controls. Can you get me a serial number?

Steve

Dave_61

Model/Serial

My boiler is a Lochinvar Efficiency+ (model EBN300). The serial # is F006579 and the Control # is M9.
I looked at where the heat exchanger is located, but in order to actually see it, it involves removing the gas manifolds...something I'd rather leave to the pros.
But if you can get any info on an accessory from Lochinvar that would use an outdoor temp sensor to control my burners, I'd really appreciate it.
Thanks.
Dave

Joe Mattiello

Taco rep for price, and availability

The PC702 is a two boiler staging control, so that wouldn't work. Call me if you have additional question, or concerns.

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com