burnham v7 boiler ODR possible?

crazy907ak

i have a 1996 burnham v7 boiler that seems to be running just fine in its present condition with a tankless water heater installed. It has a holding tank installed on tankless water heater with a taco circulation pump everything working fine.... problem is i want to install ODR on it but im worried that it will damage the boiler given the V7's history with cracking and leaking. Any body done a successful ODR on this series of boiler with out it going out? I used to have a Toyotomi hot water heater on my last house and now i hate to see this boiler turned on all summer just for hot water.

billtwocase

I would

start with adding an indirect, and do away with the tankless coil system. The hot water can be prioritized, and won't be affected by ODR

Paul48

Taco

http://www.taco-hvac.com/training/how_to_install_the_fuel_mizer/learn.html

crazy907ak

Thank you

For the comments, i believe i could figure out some way to make my holding tank with a circulation pump act as an indirect hot water heater with the tankless heater built into the boiler and wire it for ODR but the real question im asking is does anybody know the particulars on why these burnham v7 boilers are cracking and would shuting them down or atleast letting them cool off as a boiler would do on a ODR in the summer time would cause the boiler to crack?

Im completely ignorant on these cast iron boiler systems and im kind of worried about how they respond over time if they were to cool off completely or if only to cool of to say 140f for long periods of time in the summer?

icesailor

Tankless, storage tanks and ODR:

An tank-less with a storage tank IS an  "Indirect". The coil is in the boiler instead of the tank. IMO.

Install the ODR. I don't know how the "Indirect" (I'll call it that) controls the boiler, but if dome through a relay, wire it so that it over rides the ODR and flips the controls to high limit. Only when the DHW tank is satisfied will the system run on ODR.

But in my opinion, it is a really good to convert a cast iron  boiler like yours to a cold start or on demand control. type. The crud developed from hot exhaust on a cold boiler is just something to be experienced and can not add to efficiency unless thoroughly cleaned every year. So, if not, you need to run at a minimum of 140 degrees.

If I thought that there was any savings to add ODR to my many systems I have had over the years, I would have done it. High emitting copper baseboard and clock thermostats do just as well for me.

billtwocase

maintaining temp

that is a tankless heater system. An indirect will allow him to cold or warm start this system, and make the indirect priority. Stand-by temps high enough to make his domestic hot water is inefficient, and by changing things now will not shorten the life, or cause it to crack. The "V" series boiler issues were there from day 1. Some showed up, some didn't. Cracks were horizontal on the right side, about 1/2 way up, and just below the clean outs. Thin and poor castings.

icesailor

Indirects:

A coil inside the boiler in the boiler water is an indirect coil. A indirect coil inside a tank is an indirect. A hot water coil inside a shell, surrounded by steam is still an indirect coil. It doesn't matter where the coil with potable water inside the coil with a fluid of unknown source or quality is, its still an indirect. coil. A Pipe buried in the ground, in water, to extract heat from groundwater is still an indirect. It doesn't matter where it is located, if there is potable water on one side and a fluid of some other quality,that it extracts energy from.it is an indirect.

Boiler, tank combinations like Heatmaker gas boilers used the tank that the boiler sat on as a buffer tank for the heat system, giving it a large volume of water for the potable water coil to drag energy out of the heat system. The indirect coil will never become coated with scale on the outside but will on the inside from potable water with high dissolved solids (hardness in the form of calcium) but will clog on the outside if the boiler water is piped through the inside of the coil and the hot coil is exposed to the high hardness water like top performers or SuperStors.

It is far easier to clean a coil from the inside than one dirty on the outside. You have to pull the coil out. Try that on a SuperStor.

If you have a boiler with a "tank-less" coil in it, why abandon it when it is no different than buying a dedicated indirect heater and installing it. Therefore, abandoning a Indirect coil, just because it isn't where you want it?

I see a lot of homeowners post here that are so cheap, they need an can of WD-40 to stop the squeaks when they walk. $50.00 will loose you a job, no matter how much more valve they might get for their extra $50.00. How many times have you quoted $X+++ to do an indirect on an existing system and never heard another word because they wouldn't open the wallet when, for $X - or - -, they would consider it and do it? I speak from experience.

People know what they are willing to spend. More, and they won't spend it. Less, and they will consider it. People like options.

But that seems to be my minority opinion.

billtwocase

all that aside Ice,

he has a 16 year old tankless and possibly the aquabank is the same age. They are probably both on the downside of their life expectancy, and lower temps will certainly be tell tale on how dirty the coil is on the recovery side. If and when that boiler goes, an indirect is better matched to a 3 pass, and they have no coils in those boilers. I still have tankless coil boilers out there. They work for the most part, just not the most cost effective

Paul48

Savings

I would think that there would be some savings associated with a control that would vary the hi-limit based on outdoor temp.I think realistically 5-10%. I am not a fan of cold start for cast iron boilers. Even with annual cleaning of mine, sections were clogged solid with crud. The boiler lasted 12 years. I wouldn't take a boiler as old as yours, and change it. I'd take the little savings from the ODR and let the boiler live out its life as a warm start boiler. I'm just a homeowner / machinist,and this is just my experience.

icesailor

In that case,

In that case, a replacement, an indirect is a good call. There aren't coils in dedicated gas boilers. And gas is what most are switching to, because as sheeple, it's the thing to do.

My comments are to the one(s) who have tank-less coils inside oil boilers that don't perform well. Running a boiler at 190 to 200 operating temperature with burned out elements in the mixer is a terrible thing. A storage tank, connected to the coil lets you drop the high limit to 160 or less and the operating to 140 to 135. At a much lower price than a dedicated Indirect like a SuperStor, TT or Top Performer. And if you need hotter system water in the coldest months, just turn up the high limit a tad. A Hill William form of third world ODR.

That's what my comments are in relation to, not a new install from the beginning. They are only to potential customers who have a boiler with a tank-less that is under performing.

If I found a leaking Indirect and it needed to be replaced, would I try to switch if there was a tank-less that was not being used? Not likely. If I had a leaking storage tank, connected to an internal boiler tank-less,would I suggest an Indirect? Highly unlikely unless I gave the customer a choice so they knew the difference in price. If you gave a price to convert to an indirect and didn't give a price on replacing the storage tank, and I gave them the choice of either, do you think you would get the job? Not likely.

Options my friend. Everyone likes options.

icesailor

ODR:

Paul,

Complete ODR on that set-up means that the boiler will be running at below 140 degree temperatures for most of the year. Adding a storage tank and using the existing boiler controls already in place, will give you what is almost ODR. Or, you do ODR that allow the operating control to over ride the no call by the ODR. Which is just another form of an operating control.

And judging by the crap I am seeing in these Mod Con gas boilers when they get cleaned because they don't need to be cleaned, would do well by trying to extract heat from evaporation from flue gasses. I have an acquaintance that just had his SS Giannini SS heat exchanges completely fail because of some air cause. It looked like Swiss cheese. The people telling him that it was vented wrong are using air reasons to explain it. I'm hearing tales of 10 years on these boilers. Welded steel oil and gas boilers last longer that. I built a house in 1972 and it is still going strong with the Weil-McLain 562 oil boiler with a Carlin 100CRD. My present 12 YO WTGO-3 with a EZ-1 runs like new.

Its how it is going to be run. My comments are to an old well running boiler. The author made no mention of a failing boiler. Just that he thought or was told that an indirect was the way to go. My comments were to the fact that he already has the indirect. All he now needs is the tank.

And more importantly, true, complete ODR would raise hell with his boiler.

crazy907ak

thanks everyone for experience and opinions

I think given what i've read here I or the boiler anyway would be better off leaving off the ODR and going with a low water cutoff of 140 and a high of 180 with there own separate differentials like the Beckett Aquasmart would do but not shut off completely. I have been told to buy an indirect from my service guy and an ODR and since i was planning on buying the Aquasmart anyway i thought i might pick up its optional ODR sensor but sounds like that could cost me my boiler.

I dont know what most service guys do but it seems to me if i listened to my guy i would have put on the indirect and the ODR (prob a tekmar 260) i would have come summer time found myself with a cracked boiler or come next service time a really scaled up boiler. Glad i didn't blindly take his word for it and do the work.



Once again thanks everyone for saving me with your experience and opinions!



I really couldnt see the difference between a really well insulated holding tank and a indirect hot water heater, given the placement of the the coil is inside the the tank or inside the boiler. Maybe some small efficiency difference in how fast the water could be heated if both where brand new. Mine is obviously not and if the coil goes out or clogs i will at that time buy either a new coil if thats possible or an indirect tank with coil.



Sorry for taking so long to follow up, im in Alaska and its -30f and i didnt want to get out of bed

icesailor

First Post:

In your first post, you said that you had a cast iron boiler with a tank-less and a storage tank. You said that someone told you that you should drop the tank-less and storage tank, and go to an indirect and go to ODR.

All my comments are addressed to that issue and that I didn't think it was a cost effective choice. If the tank-less coil is working fine at this time, it isn't plugging up with dissolved solids, why replace it with the same thing?.

What are your control settings now?

Set the "Low Limit" to 140 degrees. If you still have enough hot water when you need it, leave it there. Set the "High Limit" at 160 degrees. If it gets really cold, and the house doesn't get up to the temperature you set on the thermostat, raise the setting to 170 degrees or higher. Most houses are over radiated so cooler water won't make a difference, especially if you have added insulation or window upgrades. It will still get warm. My thing is why throw out a perfectly good storage tank if it isn't leaking.

Paul48

ODR

ICE

You're right, and that Taco has a min setting, but I forgot to take that into account when I considered the savings. It would probably be under 5%.

crazy907ak

so far no complaints

with my tenants (5plex). My min setting set by my boiler guy are low 152 high 170f with diff at 20. I have never seen it operate under 170f. I believe the zone valves are telling the boiler to kick on every time they get a call for heat instead of running the circulation pump until it hits its low (seems inefficient to me) hoping Aquasmart changes this? or is this something that is wired wrong and i need to change before installing Aquasmart?



I

crazy907ak

control connection between boiler and hot water heater

I should of cleared this question up from the start Icesailor, you asked how the "indirect" was controlling the boiler and my observation is its not it seems they have wired the built in thermostat of the electric water heater to just turn on a taco circulation pump. Since water in boiler never got below 170 it kept water hot pretty well as long as boiler is running at such a high temp i suppose it would. After i change it so the boiler drops to 140 will it still be able to keep up configured the way it is?

Paul48

Question

What type of boiler control is on there now? Typically the high limit only comes into play on a call for heat. The boiler should maintain itself  with no call for heat, a low limit setting of 152, and a diff. of 20, firing at 142 and shutting off at 162. Because you are just turning the DHW circ on with the thermostat, it should only affect the maintained temp of the boiler, and the boiler should operate at the lo-limit and diff. just as it would if you had no tank.

crazy907ak

Control

Honeywell type l8124A,C

Paul48

Honeywell

https://customer.honeywell.com/resources/techlit/TechLitDocuments/95-0000s/95-6571.pdf

crazy907ak

Honeywell control

So right now i have 8 zones total and at these temps or even more moderate temps i seem to always have atleast one zone calling for heat so boiler keeps jumping back and forth between its high limit and its own 10 point set differential?



Is this recommended ? And will my new Aquasmart change this?

I guess i can try to go research that myself.

Thank you Paul you have explained alot

Paul48

OK

That explains the boiler always at 170. What's the advantage of changing the control? I think you'll be in the same boat.

crazy907ak

Sounds like it

I havent read specificaly about this yet but im still hoping it has a different way of operating

icesailor

Control wiring:

Understand that in the world of triple acting controls, the first function of the control is to control the :high limit. When the house thermostat makes a call, it is supposed to start the burner and circulator if it isn't steam. It is supposed to run until either the thermostat is satisfied, the burner runs out of fuel, or the boiler blows up. But the high limit stops it before that happens. Then, the boiler is off until the next call. It could be off until the boiler freezes and breaks. With a "Tankless", you need a control, the "Operating" control, that will maintain a set temperature in the boiler for a time when you want hot water and the boiler will not have to try to catch up from a cold start. You need to keep a 20 degree differential between the operating control and the High Limit control to avoid arguments between who is in charge. The third part is the "Low Limit Circulator" part of the control which is also part of the low limit operating part of the control. Remember that when the thermostat calls for heat, it starts the burner AND the circulator. Run until ordered to stop. But, if the cold return water is cold, the boiler will be cold, and to keep the boiler hot for a call for domestic hot water, the Low Limit will kick in and stop the circulator. It over rides the operating control to keep the burner running but NOT the circulator.

If you have all the zone valves properly wired, whenever you get a call, it will start the burner and circulator. Depending on what brand of zone valves will determine how long it takes to open the valves and send the call for heat.

When you use a storage tank like a water heater, you do not need to wire the water heater tank into the control wiring of the boiler. When the DHW demand comes, it will cool the water around the tankless where the boiler control usually is, and the burner will start. But not the heating circulator(s). If, during a domestic hot water call come in, the operating part is overridden and the circulator starts and the burner will then run to the high limit setting. If the boiler water gets below the operating part set point, the circulator will stop but the burner will continue to fun.

I'm getting confused but you have a hot water system and not a steam system. If you have zone valves, and they are Taco 572's, and the thermostat settings aren't proper, they will cycle like crazy. If you have multiple circulators and they are not wired and controlled properly, they will drive you crazy.

It sounds to me like your problems aren't as great as you first thought. You may be in need of some quality adjustments.

True indirects like SuperStor's are really just heating zones. They are either on or off.

I hope that this is helpful. 

icesailor

Zone valve wiring:

No. If the zone valves are properly wired, every one will start the burner and run it up to the high limit setting. One, two or all.

Another way to help with short cycling with your zone valves IF THEY ARE PROPERLY WIRED to start the burner, lower the high limit to 180 degrees or lower, keeping the 20 degree differential. The cooler water will make the circulator(s) run longer

But here is something. You have 8 (eight) zone valves? Are they all controlling one circulator? If not, and there are multiple circulators, are the start relays wired through the ZC/ZR terminals in the R8124 controller? If not, there will be some of your problems with short cycling. Each set of zone valves and its circulator should be controlled with something like a Taco ZC 50* zone controller with all TT wires going to the TT on the R8124. The ZC/ZR terminals MUST be used. You may have a complicated wiring issue.

icesailor

Operating:

The way I explained is how it operates.

Tell me again what you are trying to do?

With 8 zones, your "short cycling"ay be completely normal. If your building has an 80,000 BTU load, and all zones are equal, that's 10,000 BTU's per zone. If the burner fires at 80,000 BUT net, it is 90% overfired with only one zone running.

Ron Jr._3

Indirectly heated water .

Although you might technically be right , an indirect fired water heater is not the same as what the OP has . Which is just a storage tank , booster tank , aquabooster , water bank ........  whatever you'd like to call it . 



I've installed new boilers with aquaboosters and used reset controls on the systems. We controlled the bronze circ for the aquabooster as the priority . Although the recovery time was longer than a traditional indirect , there was no complaints of running out of hot water .



As far as the longevity of the V7 and OR , it's anyone's guess . I have my 15 year old Peerless WBV on full reset for about 5 years now with no problems so far ..........  And if the boiler is coming on a few times a day to make hot water , it ain't really " cold start " ......

crazy907ak

Honeywell control

honestly wiring low voltage equipment with relays and transformers and even the the zone valves themselves is a little bit over my head at this point, im more comfortable wiring a whole house with AC. I guess ill have to educate myself real quickly .



from the link paul sent me it shows the control turning on the boiler every time it gets a call for heat until it goes over its high limit setting and if there still is a call for heat circulation pump the heat until boiler cools off to a preset 10 point differential then turns back on.



If so this would explain why the system is turning on and off so much



right now 8 zones all control one Grundfos Alpha and nothing is connecting to the ZC/ZR on the Honeywell



I looked up the controls on the new Beckett Aquasmart and it has a adjustable high limit

differential and a separate low limit differential so if i were to set the high limit differential to 20 degree setup wouldn't that fix the problem



So for overview i plan to set it up so low is at 140 with diff at 15 and high of 180 with diff at 20 so during no call scenario during summer the boiler would go to 140 and up to 155 and in winter boiler would run longer going from 180 to 160 before turning back on



if i understand this right this should double the amount of time my boiler stays off during cold days when it is getting calls for heat, letting the circulation pump pump out its heat until it reaches the 160 degree on point? fixing my short cycle problem ?

Paul48

Unseen

I think there is more going on than meets the eye. I'd go back to square one. Do a room by room heat loss, and compare that to the radiation in each room. Then total them up and see how the boiler stacks up, size-wise. It just doesn't make sense that the boiler should be operating at high limit, even with multiple zones calling. It would seem to reflect a lack of radiation.

icesailor

High Limits:

Paul, it is completely normal to do that, cycle with zone valves. Because like I pointed out, you have divided the load into 8. If they all came on at once, the boiler would probably run for a long time and cycling would be minimized. But with small zone loads, the boiler is way oversized for the load.

In the scheme of things, I think you will get longer circulator run times with few zones calling because of the latent heat stored in the mains.

If you only have one circulator, and it is powered off the C-1 terminal in the R8124, the ZC/ZR part if the control is being used. It is only when you have multiple circulators driving multiple zones that the problem occurs.

crazy907ak

So im okay ?

Logically it makes sense from my little bit of understanding of the situation

Of why this boiler is short cycling. But will my solution fix the problem ?



Sorry it takes me so long to reply

Once again thank you guys

Learning alot here about my system