turning an old gravity piping system into using a high effeciency boiler

Harvey Ramer

I would think long and hard before I put a boiler with a giannoni heat exchanger, on an old gravity system. That system has a hundred years of crap in the pipes. The giannoni has narrow passageways that can get blocked up. A far better choice for this system would be a firetube heat exchanger. They have bigger passage ways and won't get blocked as easily. You should still use a dirt separator.

As far as the circulator goes, you can be good and careful about picking the right one. You want a circulator that has a flat curve. In other words, it can move a lot of water but doesn't have the ability to generator a lot of head pressure. Look at the minimum flow rates of the boiler you choose. They will be listed in the manual. If you pump straight through the boiler, which you can on this system, make sure the pump slightly exceeds the minimum flow rate of the boiler while at max fire. That is really important! While some might disagree, I am a strong proponent of maintaining a fixed pumping volume on these gravity systems.

Many of the new ModCon boilers have the controls to do constant circulation. Doing that, coupled with ODR control will make your house feel vonderful gut!

If you find a couple trouble spots that are getting to warm, simply put a high capacity TRV on that radiator. No need to put one on every Rad.

maybemark

harvey
I'm putting in a firetube, a whn85 and also using a dirtmag.
i bought a 15-58 pump, but i am hearing that might not be good enough. I plan on flushing the system many times befor it ever enters the boiler

Harvey Ramer

Personally I would have chosen the Taco 007 for this one.

Consider the Fernox cleaners and inhibitors to clean the system and protect the new boiler. I have had excellent results.

icesailor

@Harvey Ramer:

"" If you find a couple trouble spots that are getting to warm, simply put a high capacity TRV on that radiator. No need to put one on every Rad. ""

As far as I am concerned, this topic is over. Your comment quoted above.

Have you ever worked on a hydronic system where you forgot to close the flow check and the system ran on gravity overnight until you got there to close the valve? The circulator didn't run because the thermostat was satisfied. Yet, each radiator in the whole system was the same temperature.

If you take any pumped system, whether it was a former gravity or a baseboard series looped system, set the limit to 130 degrees, and turn on the circulator. Make it run for as long as you want. After some unknown time, every radiator in the entire system will be the same temperature. You can not have a radiator that is significantly warmer than any other radiators. Even if you have an added circuit to a gravity system that is installed improperly, like a long flat run off a main added later, sooner or later, even that radiator will be the same temperature as the rest of the system. If it runs long enough. As long as the energy source supplies the same temperature water in the quantity needed, the whole system achieves balance. Like a steam system without the steam.

SWEI

icesailor said:

Even if you have an added circuit to a gravity system that is installed improperly, like a long flat run off a main added later, sooner or later, even that radiator will be the same temperature as the rest of the system. If it runs long enough. As long as the energy source supplies the same temperature water in the quantity needed, the whole system achieves balance. Like a steam system without the steam.

...which is exactly why modulation with constant circulation and ODR make these old systems sing. The high water volume makes for very happy boilers.

nicholas bonham-carter

What about an asymmetric multi-boiler setup, with a new smaller modcon sized for the most prevalent warmer winter temps, while still keeping the old boiler?--nbc

https://forum.heatinghelp.com/discussion/comment/1320268#Comment_1320268

maybemark

Harvey
I bo0ught the 15-58, should I get the 007's instead? i bought them online, so i can't return them.
Thanks for the suggestion on the cleaner. Just put it in the system, and let it circulate but not thru the boiler?

maybemark

Harvey
Do you think it's very important that i have the 007, so critical that i should get rid of the 15-58?
also, the 007 for the boiler pump, heat pimp, and domestic pump?
thanks
mark

Harvey Ramer

I guess it's up to you on the circulator. Maybe try the one you have, in speed 3 and if it's noisy (cavitation) or you get uneven heating, swap it out for the 007. I would put it on the return side so you have a little head resistance at the outlet of the circ. You still have to put the expansion tank and fill valve in the pipe on the inlet of the circ. The air separator can go on the supply side.

That is assuming you are piping straight through the boiler.

The cleaner works best when the boiler is in operation and the water is hot. I would put it in whiler the old boiler is still intact and operating. The max amount of time for the cleaner to stay in the system is 2 weeks. After you are done you have to flush the system really well. Then add inhibitor F3 to the system when you have the new boiler installed. One pint does 26 gal, for both the cleaner and the inhibitor. It doesn't hurt a thing if you get a little extra in.

Harvey Ramer

icesailor said:

@Harvey Ramer:

"" If you find a couple trouble spots that are getting to warm, simply put a high capacity TRV on that radiator. No need to put one on every Rad. ""

As far as I am concerned, this topic is over. Your comment quoted above.

Have you ever worked on a hydronic system where you forgot to close the flow check and the system ran on gravity overnight until you got there to close the valve? The circulator didn't run because the thermostat was satisfied. Yet, each radiator in the whole system was the same temperature.

If you take any pumped system, whether it was a former gravity or a baseboard series looped system, set the limit to 130 degrees, and turn on the circulator. Make it run for as long as you want. After some unknown time, every radiator in the entire system will be the same temperature. You can not have a radiator that is significantly warmer than any other radiators. Even if you have an added circuit to a gravity system that is installed improperly, like a long flat run off a main added later, sooner or later, even that radiator will be the same temperature as the rest of the system. If it runs long enough. As long as the energy source supplies the same temperature water in the quantity needed, the whole system achieves balance. Like a steam system without the steam.

@‌ice
You make my point exactly. Every radiator gets warm, therein lies the problem. Back when these systems were installed they didn't have TV's, gaming consoles, computers and all this stuff. Now people fill a certain room with a bunch of electronics or the take one small room and turn it into and office with computers, printers, etc.. These rooms will overheat only while the electronics are in operation. Also bedrooms, many like them cooler.

When I come on the scene, I pull a TRV out of my hip pocket and make their problem go away

icesailor

"" ...which is exactly why modulation with constant circulation and ODR make these old systems sing. The high water volume makes for very happy boilers ""

So, constant circulation. A pump running 24/7. Kind of wasteful isn't that?

The High volume has a low velocity. 2 GPM. So, if you started off with a 4" main, and had 1" branches to the radiators, and the flow was 2 GPM through the 1" pipe, does that mean that the water flowing in the 4" pipe is 4X slower? Which I mean is velocity through the pipe?

The ultimate gravity systems that I saw, only had a mechanical thermostat that started a burner. It heated the water until it reached an equilibrium with the heat loss to the outside. And shut off the burner. Until the heat loss overcame the heat in the room. Even a Potable hot water heater only runs when there is a demand.

Constant circulation just evens out the highs and lows. Just like Mod-Con's and "I" Series, 4 ways.

maybemark

I do have a few rooms hotter than others, but what i do, which is simple, I turn down the radiator valve, this helps dramaticly, without purchasing anything.
I am a carpenter general contractor, I don't know much about hydronics, but have learned alot from this site and your people. to me, it seemed simple to just turn down the valve.
harvey, did you answer me, when you say get an 007, is this for all pumps, or just the boiler loop?
I have no idea how much water i have in my system, so, how do i know how much cleaner and inhibitor to purchase?

icesailor

nicholas bonham-carter said:

What about an asymmetric multi-boiler setup, with a new smaller modcon sized for the most prevalent warmer winter temps, while still keeping the old boiler?--nbc

https://forum.heatinghelp.com/discussion/comment/1320268#Comment_1320268

I would consider that to be a kin to a 4-way mixer. Connected to a boiler and the temperature in the system controlled by the 4-way. The boiler van be hot for indirect use.

The boiler can be a cold start, because the Taco "I" Series, holds the water in the boiler until it reaches the set point to start mixing.

maybemark

harvey
I see there are several 007, do i just get the one with the ifc? or do i get something different? I did read something that the whn85 can have variable speed pumps on them? or is this totally different than what i am looking at?
Maybe these questions sound very dumb to a person in this proffession. i hope you can put up with me, and realize, i am trying to learn
thaks
mark

icesailor

@Harvey Ramer:

"" You make my point exactly. Every radiator gets warm, therein lies the problem. Back when these systems were installed they didn't have TV's, gaming consoles, computers and all this stuff. Now people fill a certain room with a bunch of electronics or the take one small room and turn it into and office with computers, printers, etc.. These rooms will overheat only while the electronics are in operation. Also bedrooms, many like them cooler.

When I come on the scene, I pull a TRV out of my hip pocket and make their problem go away ""

Yes but, people tend to set the thermostats lower, and because of the cooler radiators, you get less drafts. The TRV's are nice. They aren't a do-all substitute.

Where TRV's shine is in rooms that face prevailing cold winter winds. They are cooler on windy nights and the heat from those rooms infiltrates to the lee side rooms. Same with East facing rooms with morning sunshine. If you have a house that faced due South, and had four equal rooms, which room should you put the only thermostat in? The NW one. It gets the cold in the winter wind, and little sun. An East facing room overheats in the morning, the SW room overheats in the afternoon. The old dead guys always told me that they put "a little more" radiation in the NW room or the North side of the house.

SWEI

nicholas bonham-carter said:

What about an asymmetric multi-boiler setup, with a new smaller modcon sized for the most prevalent warmer winter temps, while still keeping the old boiler?

With a heat loss of 76k?

maybemark

swei
I talked to someone on the phone from this site last night, he suggested just an 007 just single piping for my boiler and heat. He is saying this because of my old converted gravity system, he feels this is simple, and will work great.
how do you feel about this?

SWEI

It will almost certainly work, though raising ΔT to maximize boiler efficiency might take a bit of experimentation. I would probably start with the boiler's internal circulator and see how it performs at various speeds.

nicholas bonham-carter

I was thinking of playing around with the slantfin app to find the heatloss at a warmer winter temperature, (one which would be more frequent than the design temperature). That way the smaller undersized boiler would handle most winter days, and if it got down to design temperature, the old faithful behemoth would take up the slack for that relatively short time.--NBC

SWEI

Keeping a massively oversized CI boiler, buying the additional controls, and installing the additional piping? Yikes.

nicholas bonham-carter

The oversized boiler may only run 2-4 days a year, when the little one cannot keep up, and it does not have to be broken up and taken out!--NBC

SWEI

Mark is trying to get his boiler replaced, not run a science project. Adding a $600 controller and additional piping to his already confusing set of recommendations is not something I would be recommending here.

maybemark

swei
thank you for your words.
and about yesterday, maybe i am the one to be appologizing
mark

Paul48

This has gotten so convoluted, I have no idea where the OP has been taken with his quest. Is he piping P/S, or pumping through? The 15-58 speed 1 is listed as boiler pump P/S at a couple different fractional heads. The 007 is listed as one alternate. Even with the low head of the gravity conversion, wouldn't that take the 007 off the table for pump through consideration?

Gentleman.....Can't you see the frustration in the OP's postings? He has chosen to go this route. Lets help him with his chosen path and stop arguing " the price of tea in China".

maybemark

Paul
Thank you
I have not made up my mind, on what route to go for piping, it was suggested to pipe thru. I am asking others, does this sound like a good idea.
I myself is a general contractor, and i work with an old school plumber, this system is for my own house.
fred my plumber is not convinced on the HE boilers, because he has only put a handful in.
I have taken it on my own, to try and gain knowledge and make a good decision. fred will do whatever i ask (almost anything).
I came to this site to gain knowlege, which i feel i have a little more knowledge today that 4 days ago ,get ideas from people and for help.
So far i have ordered a whn85, and a Loch 40 gal indirect, plus ordered a bunch of other suggested parts.
Some of the parts i ordered was 2 15-58, 1 dirtmag, air seperator and expantion tank, plus other mis things
Any thought and help with the piping would be appreciated, also, any thoughts of materials needed also appreciated
thanks
mark

maybemark

another new question.
I see that ph is very important for the system.
i live in chicago, and the water right out of the faucet ph is 7.8.
I took a sample of the old water in my system, and my test kit (fish tank test) only goes up to 8.8. the system topped the scale, so, it might be alot higher in ph than the 8.8.
can i get some feedback?
another question
I know my systems pipes are almost 100 years old, filled with particles, it even showed in the sample i took this morning. I am planning on flushing the systems sever times before i install the new boiler.
Are these chemical cleaners good to use, or, should i stay away from them?
thanks
mark

Gordy

My thoughts were maybe p/s with the 007 on secondary and the onboard 15-58 controlling the primary. If you use steam heads formula for 847 edr the 007 is a close match to the system. His formula calls for 20 gpm to mimic gravity circulation.

SWEI

Here's what we do:

First, flush the old system using freshwater at line pressure. Close off whatever valves you can in order to force the water through smaller portions of the system in sequence, letting the water run until it is clear.

Next, fill with a hydronic cleaner (e.g. Fernox, Rhomar) and run the boiler at a high temperature (like 180˚F) for several hours or even days. Drain the DirtMag several times during this process, refilling as necessary to maintain pressure.

Lastly, drain the entire system and refill using fresh water with an inhibitor/conditioner. Be sure to open the drain on the DirtMag fully (the big chunks stay in if you just crack the ball valve) a few times during the first month, then once a month or so until that runs clean.

maybemark

swei
you think i should clean out the system with the new boiler, and not use the old boiler to take the debis in the lines?
Won't i be possibly subjecting the new boiler to crud?

icesailor

If I could figure out how to find photo's or a mystery past discussion, I would show you how few fittings are needed. No added controls. Just what's there. Less than 10' of 1 1/4" copper pieces, adapters, ells, and a added Wilo Circulator. Two Tridicator gauges to check Delta T and flow. You make it sound so complicated. It wasn't.

Someone else did the oil burner. They told the owner he needed a new oil tank because it leaked. It leaked because the caretaker took a plug out of the top of the oil tank to sound the oil with stick. The oil came out of the loose plug. The gauge had a bad float that sunk. I replaced the fill so it worked. The caretaker still insisted on using a stick. You must not deal with the average run of the mill crazies that some of us have to deal with. Like the lady who walked throughout the house, ringing a bell, to get the energy in line. Or the family who had a boy that loved snakes. He didn't tell his parents that he was missing a snake. I found it behind a toilet I was fixing when it hissed at me. Or the mother snake that met me at the bottom step of a wooden ladder hissing at me because her baby snakes were caught up in a 1 HP 56 frame pump motor. Or, the baby rabbits inside a pump pit when I pulled off the cover. How do you get baby rabbits or a snake out of a pump pit? Carefully. Neither one wants to be caught. Or bats in an attic, flying around, and they can't get away. Little Brown Bats are smaller than my thumb but look huge when flying. My life won't change, no matter what the OP does.

Memories. And experience by trying new things. Some work, some don't. Like Staple Up heating.

SWEI

The freshwater flush can be done any time. You could use the cleaner with the old boiler, but I would probably do it again with the new piping in place. Webstone Ball Drains and Isolator Flanges are not expensive and really facilitate both cleaning and service.

We use a purge cart and a 20μ pleated paper filter when we do this.

maybemark

swei
i am totally lost. I guess i was hoping for a simple one time way of doing this.
thanks anyway
mark

maybemark

At what point in the system do i put the drain and ball valve to clean my old system. And, how do i install the fresh water and or cleaner to my system?

jumper

I've seen this way of piping.Old boiler is replaced by full sized pipe with check valve. New boiler is teed in (monoflow fittings?) on either side of check valve. This way boiler circulation is decoupled from heating circulation. Instead of zoning apply control valves to individual terminals if you can.

maybemark

Jumper
I'm sorry to say, but I don't understand what you mean

jumper

I don't know if this will help. Pipe the new boiler in parallel with old gravity system. That way you have gravity circulation with a boost from boiler circulator. Go to a boiler's website and find instructions for replacing big boiler with multiple small ones to get the idea.Google SlantFin Caravan for example.

TonyS

Best way to pipe them is straight through with minimal pumping. Gravity systems are figured at 0 pressure drop and are piped two pipe direct return so over pumping will just cause problems with short circuiting. Primary secondary is not needed.
You will need to know the heat load of your home and the EDR of your existing radiation to properly set your heat curve. I have found that most 100 year old homes have been greatly improved over the years and I have never had to run more than 140 degrees on design day( I use 0) That leaves 120 return temps on even the mildest days. You will see BIG savings using a modcon on this type system. I usually use a Triangle tube Prestige that comes with a 3 speed grundfos pump. I use speed number one.
A couple of thermostatic radiator valves in the rooms you want a little cooler and you will have a very nice system.

maybemark

Tony
Someone else sugested the same thing you said, 1 pump for both the heating system and the boiler, no loop.
I am going with the Lochinvar whn85. Talked to the tech, they recomended the loop.
86. I like the idea of what your saying, but i would hate to go against, and loose my warentee.
87. I know the heat loss, which is 76k and i haveway to much radiators, but I forgot the number. the lachonvar comes with the same pump as the TT.
88. I have valves on all the radiators. i just work with the valves to adjust the temp
thanks for your input
Mark

TonyS

Many of the techs today are unfamiliar with gravity systems. The exchanger in your Lockinvar is the same as Triangle tube. Designers figure piping loss in a gravity system as zero but in reality it is negative because it is self circulating...just add heat. There is no reason for pri sec piping because there is no added pressure drop. Working in an old PA city I have finished quite a few of these systems. They work great. Your pump is only there to get the water moving...not to push it through the system. Let gravity work the system as it was intended. Two pipe direct return systems do not like to be pushed, they have a habit of taking the shortcut back to the boiler.

maybemark

Tony, i am not sure if you know, my house a very long time ago was gravity fed, the last 2 units where pump fed. The unit that is in there now is a 35 year old burnham that uses 1 taco 007 pump.