Location for Feed and Return of Boilermate Off Primary Loop

I'm running my primary loop through my old boiler and then supply two zones with two returns before the loop goes back into the WL 110 which supplies the heat.

Where would be the best location to tap into the primary loop in order to supply the boilermate without having an issue with the water flow short circuiting the old boiler and going through the boilermate instead?

There really isn't without isolation of the OB

All you can hope for is something that will sort-of-work so pick the most convenient and shortest run - and live with the result === Result?? It depends

isolate the OB into a true Primary/Secondary system and you will have something

Yep, the result sure does depend.

I'll have to dig up my books again and look into that secondary loop, because the boiler mate does have it's own circulator pump. I'm pretty sure the way it's plumbed now I'm not getting the advantage of having all the extra mass of water in the OB, because I still get a huge temperature drop on the return from the zones.

Add two closely spaced tees in a convenient spot on the main loop for the indirect. A weighted flow check should prevent ghost flow through the indirect, a zone valve definitely will.

Rob R. wrote:Add two closely spaced tees in a convenient spot on the main loop for the indirect. A weighted flow check should prevent ghost flow through the indirect, a zone valve definitely will.

That I can do, and would be the easiest solution. A weighted flow check valve...hmmm, more things to learn....

kstills wrote:

Rob R. wrote:Add two closely spaced tees in a convenient spot on the main loop for the indirect. A weighted flow check should prevent ghost flow through the indirect, a zone valve definitely will.

That I can do, and would be the easiest solution. A weighted flow check valve...hmmm, more things to learn....

I strongly advise against this

Sting wrote:

kstills wrote: That I can do, and would be the easiest solution. A weighted flow check valve...hmmm, more things to learn....

I strongly advise against this

A caution that I respect.

Why?

As it stands, I do have a primary-secondary loop, but I'm pulling the boilermate off the primary loop close to the boiler discharge and adding it back in after the old boiler. That's why I think I keep short circuiting the OB once the boilermate's call for hw ends.

kstills wrote: As it stands, I do have a primary-secondary loop, but I'm pulling the boilermate off the primary loop close to the boiler discharge and adding it back in after the old boiler. That's why I think I keep short circuiting the OB once the boilermate's call for hw ends.

This supply and return point is good - and yes because you have a {ummmm whats the HR friendly term} -- lets use "hybrid" piping plan -- then yes you will have drama on the off cycle of this loop

That can be addressed in several ways
first off - correctly build a P/S system that will isolate the Primary loop from the boiler loop(s) and from the load loops -- and you won't have 'short circuiting"
ok maybe thats asking too much
well then you have to control the flow with manual - gravity - or automatic controls and proper pumping. Its not as simple as picking the magic spot because in this system is will not exist

OK maybe that was the cold harsh reality of the day but -- Let me get back to you with a better answer. oh this is my fav... I Think

step back and think like the water



find a way to make it go where you want it to -- not where it wants to

Taking out the boiler mate from the equation, the primary-secondary loop was set up to mimic the information from the Halloran book (sp). Tee's were spaced within the distances advised, the pumps are on the supply side to the two zones and the piping was installed as a reverse return (which has done an admirable job of balancing the radiators, something I had a devil of a time with before).

So why wouldn't the boilermate act in the same manner? Hook it up with closely spaced t's to avoid a pressure drop and call it a day?

I suppose the wild card is pushing against that 40 gallons of water mass in the old boiler, however once the flow starts, that should not be an issue. Or will it be?

Well maybe I misunderstood how you had this all piped


So if you have followed the knowledge of the books - then isolating the indirect as outlined will work fine. My rub is if you do not get the spacing exactly right you may- could- might (you mileage may vary) have less than boiler temperature water and insufficient energy to correctly run the storage -- In my world, close spaced loops are to isolate heating sources -- not loads

I will use them when I am building a temperature reducing loop - thats not what you want

if you use a flow check and or a pump with a flow check to charge and rest the indirect DHW tank - then you should be able to overcome the application mistake of using close spaced tees - this will also prevent ghost flow thru the indirect but it will not stop ghost flow thru the OB because --->as you stated above <---you have the OB in series with your primary loop and not parallel to the primary loop -- remember the only way close spaced tees work is if there is circulation across them

This paragraph above is the premise I am operating on and if that is incorrect then trash all the drivel I have written so far

you may (also) need a full port flow check on the supply piping OUT of the OB- do you have 24/7 circulation on your primary loop?? if not, is there a reverse flow in the primary loop that is your "short Circuit"???? Often is difficult to diagnose from across the public internet with snips of information and only moments of cognitive thought between binges -- AGAIN think like the water - make it go where you want it to in the easiest way possible - if you have the books this is already drilled in and there is likely 3 ways to do it right -

Kind Regards
Sting

Well, you're right about those brief moments of cognitive thought, as this is all coming back to me slowly.

The primary runs 24/7, with a Taco 007, iirc, which is putting out about 19gpm or so. My zones were fitted with variable speed taco pumps set to the lowest setting which is ~7gpm, so even if I have calls from both zones at once I have sufficient flow in the primary to make the system work properly.

I think.

And truth be told, I've never had a problem with heat calls to the zones, in fact the new piping scheme means zone 2 (upstairs) has all the radiators coming up to temp at the same time (and I thank you for pointing me in the right direction to make that happen). Zone one has issues because of a mismatch in radiator sizing, and will have to be addressed by zone valves, I think, at some later date. However, since the radiator output of the downstairs far outstrips the heat loss for the entire house, this hasn't been a problem in terms of comfort.

What has been at issue is the flow through the boilermate, or more accurately, the use of the OB as a way to increase the heated mass of the system thereby reducing thermal shock on the boiler because of all the cold water flooding back from the radiators. I had also hoped to decrease the recovery time of the WL 110, which in high mass systems seems to be very long indeed. That hasn't seemed to work, and in fact I haven't seen much change in performance since I replumbed the system.

What I have seen on more than one occasion is the high temperature limit on the boilermate go off, which would only happen if the primary loop was cycling through the boilermate instead of the OB. Thinking like water, I assumed this was because once the flow started through the boilermate, it would prefer that route instead of having to once again push against that 320lb mass of water in the OB.

Long story short, feeding the boiler mate from the primary AFTER it leaves the OB would address that issue, if indeed that was the cause of the problem.

kstills wrote: which would only happen if the primary loop was cycling through the boilermate instead of the OB.

By now someone is usually calling for my hat to be handed to me with my head still in it -- BUT--- I cannot get past your description of the primary loop operation. My rub is it cannot possibly cycle thru anything - it is supposed to be simply a loop of energy bearing liquid constantly in motion by its own circulator in a circle of pipe correctly sized for the load is serves. The fact that you have your OB in that loop is interesting/unique but it doesn't change the function of a primary loop -- EXCEPT for the fact that if the OB fires - the energy is immediately added to the loop - further if the OB is drafting products of combustion - or simply basement air up --- the stack - well its a huge energy parasite

now -- back at the ranch -- do you have the Boiler mate drawing energy off the primary loop with a supply and return point - with its own zone valve or flow controlled circulator? -- or is it in series in the same loop with the OB? if yes - this will never work

kstills wrote: Thinking like water, I assumed this was because once the flow started through the boilermate, it would prefer that route instead of having to once again push against that 320lb mass of water in the OB.

if correctly piped--- the boiler mate should only draw energy from the primary loop -- the primary loop circulation should not impact the boiler mate supply or return piping when it is not calling for heat

just as the primary loop circulating will not send energy out to any of the other loads with out those loads calling for heat --- when correctly configured

kstills wrote: Long story short, feeding the boiler mate from the primary AFTER it leaves the OB would address that issue, if indeed that was the cause of the problem.

It still depends

I know you have your OB in some sort of loop for mass energy storage

this is a throw back to Wood boiler piping - Storage is best kept in the black rocks until its needed

I know your skeptical about boiler protection - this is why you isolate your Oil and your coal boiler in boiler loops that feed energy into an independent primary loop. It makes NO difference what temperature the primarily loop runs. You protect the COAL boiler from the primary loop by only pumping that boiler when it is above 140. should the primary loop be cold enough and the call for heat be large enough that the coal boiler cannot keep up - then control should stop pumping the coal boiler until the differential of the(coal fired appliance) aquastat allows it to recover - in this control set the coal boiler runs in the stat differential hi low only and the boilers can never be shocked - it also allows you to allow the OB to come on independently if the house temp falls too far because of a solid fuel drama - or even if the solid fuel appliance is undersides on those "special" cold nights.

Think of a primary loop as a resource - injected with energy from one or many appliances - and then use that pool of energy to fund whatever load you have. Use all that crap I spew of system balance to control the flow of energy out into the zones with the correct temperature drop per loop - and further eliminate the possibility of over shoots and shocks - Balance gives comfort

Sting wrote:

kstills wrote: which would only happen if the primary loop was cycling through the boilermate instead of the OB.

By now someone is usually calling for my hat to be handed to me with my head still in it -- BUT--- I cannot get past your description of the primary loop operation. My rub is it cannot possibly cycle thru anything - it is supposed to be simply a loop of energy bearing liquid constantly in motion by its own circulator in a circle of pipe correctly sized for the load is serves. The fact that you have your OB in that loop is interesting/unique but it doesn't change the function of a primary loop -- EXCEPT for the fact that if the OB fires - the energy is immediately added to the loop - further if the OB is drafting products of combustion - or simply basement air up --- the stack - well its a huge energy parasite

The OB is disconnected from both a heat source and venting. Essentially, it's a cast iron resevoir of extra water to used to overcome the limitation of a 12 gallon boiler trying to heat 50 or so gallons of water in the system without the water temperature in the boiler dropping 30+ degrees and then going through a 10 minute recovery.

To be fair, once the temperature gets colder and the boiler is running normally, this is not a noticable issue.

now -- back at the ranch -- do you have the Boiler mate drawing energy off the primary loop with a supply and return point - with its own zone valve or flow controlled circulator? -- or is it in series in the same loop with the OB? if yes - this will never work

Well, the answer is yes, but to the first question. The boilermate has it's own circulator, and that kicks on when it calls for heat. The boiler mate is plumbed into the primary, with the feed coming just off the boiler (ahead of the OB) and the return going back into the primary just after the the OB.

kstills wrote: Thinking like water, I assumed this was because once the flow started through the boilermate, it would prefer that route instead of having to once again push against that 320lb mass of water in the OB.

if correctly piped--- the boiler mate should only draw energy from the primary loop -- the primary loop circulation should not impact the boiler mate supply or return piping when it is not calling for heat

just as the primary loop circulating will not send energy out to any of the other loads with out those loads calling for heat --- when correctly configured

Which apparently means the boiler mate is not plumbed in correctly.

I do not have the same problem with the zones, but the tees are very close together for the supply and return. With the boiler mate, the feed and return are seperated by 12 feet or so as the water flows.

kstills wrote: Long story short, feeding the boiler mate from the primary AFTER it leaves the OB would address that issue, if indeed that was the cause of the problem.

It still depends

I had meant to type '......should address that issue.......'