Baseray cast iron for Slantfin aluminum?

JeffGuy

As I explained in another post, I have two zones in my house - the first is a 100 year old gravity system with big cast iron radiators (16 of them on three floors). The second zone is a big open familyroom/kitchen addition to the old house that has 24+14+2+2+3+2+2=49 feet of slantfin. There is a thermostat on each zone, but there are apparently no check-valves on the zones, so that when the slantfin zone if calling for heat, there is also substantial flow into the gravity zone.

 

This causes a problem: the slantfin zone is always about 10 degrees colder than the rest of the house. Not because it is under-radiated, but because it cools down so quickly compared to the radiators which retain their heat so well. So I always figured at some point I should replace the slantfin with cast iron radiation. I just didn't expect to find any now, but while researching for my boiler I found an ad for some baseray that had been carefully removed from a house, so I bought it before I could change my mind.



From the reading I've done on this site, the cast iron baseray should (I hope) be a better match to the old radiator zone since they it will retain heat better.

 

I bought 14+14 feet of the baseray. It is the older 6" high pieces in surprisingly good shape. So if I replace 38 feet of the slantfin with 28 feet of the baseray, and leave the other 11 feet of slantfin in place (all in a single long loop) what should I expect? I assume I will want to replace the rest of the slantfin with cast iron eventually, but is it OK to start with this part now or is it important to get all the slantfin out now and not do it piecemeal? Or is it possible that the 28 feet of baseray will give as much or more radiation as the 49 feet of slantfin so that I could just put in the baseray I have and pull out all of the slantfin?

JeffGuy

Hoping

I'm hoping for some input. Have I left anything out - or is it never done to take out slant-fin (I have the Slantfin Multi-Pak 80 baseboard now) and replace with Baseray? If my whole house was Slantfin I wouldn't consider removing it - I am just hoping to get a better match with the cast-iron radiators in the rest of the house.

Eric_32

Here's my thoughts...

Your best bet is to put pumps on both zones with an IFC, (integral flow check) or you could install 2 zone valves one for each zone and have one pump for the whole house.

you can not really have to zones with out a way to stop flow to the other when one of them is firing the boiler unless there is a check or zone valve on them. 



You probably have a good 2" (or more) supply/return for the gravity main from the boiler, it will have to be reduced down for the circulator flanges to either-    1 1/2" or 1 1/4", which will not be a problem now that it is pumped. If you do go this route, use flanges with ball valves built in, so if ever the pump fails down the road, you won't have to drain the 300-gallons of water in the system to change the pump.



As much as I love CI baseboard,

The cast iron baseboard on gravity won't do well because of the 3/4" tappings on it, compared to the larger piping to the gravity rads.

JeffGuy

Thanks

Thanks for the answer. System is being worked out now. We'll definitely get the two zones pumped separately with flow checks and there will also be a primary pump for the mod-con boiler. Thanks for the advice on the flanges with ball valves (not something I've heard of but plumber probably has).



So that will solve the problem of the zones bleeding over into each other without requiring changing out the slant-fin baseboard.



But is there any other advantage to replacing the slant-fin with cast iron baseboard? Or am I better off leaving the slant-fin zone alone? Is it just as good to have one zone with radiators and the other with slant-fin baseboard as it is to have one zone with radiators and the other with cast-iron baseboard?

Eric_32

As long as

The different types of heat emitters are not on the same zone so it will work beautiful either way you decide to go. The copper fin will cycle more frequently than the cast will but it will do fine and the checks will prevent heat from crossing over the "off" zone.

I see many times people remodeling a bath or kitchen and want to remove a radiator and replace with copper fin. It never works right on the same zone together.

Good Luck with the new boiler!

CMadatMe

Heat Loss

Was a room by room heat loss done of the home? Did someone compare the loss to the existing rads and new baseray and come up with a heating curve or did they plan on just banging the reset off 180 degrees.



I ask because your investing in a high efficiency boiler, should you not get what you are paying for. It isn't high efficiency out of the box, just capable of being high efficiency.

JeffGuy

Heatloss

I did do a room by room heatloss using the Slantfin Hyrdonic Explorer program. It came up with 160,000 using indoor temp of 68, or 165,000 using indoor temp of 70. And frankly I think I was pushing it (overestimating insulation in walls) to get a number that low. (I have a very large house with three floors and high ceilings and lots of original windows and six fireplaces - frankly for a house as old as mine - 100 years - it is hard to estimate what to use for insulation factors unless you have done major demolition which I haven't).



The only Alpine's that I am offered by the gas company in that range are the Alp150 with an output of 143,000 and the Alp210 with an output of 200,000. I wish I was being offered one in between these two, but I'm not. I have agonized a great deal over the decision to go with the larger boiler, but I have convinced myself that given the size of my house and my optimistic estimations on insulation factors, and the huge amount of water in my gravity pipes and radiators, and given the fact that a mod-con will modulate down from its max when less heat is called for, that it is the safer choice, with little downside.



Is this wrong?

CMadatMe

Vitodens

If your not stuck on the Alpine then look at a Viessmann Vitodens 200 WB2B-45 which max input is 160k. Better heat exchanger construction as well as warranty and better control in my opinion.

JeffGuy

Vitodens

The 2B-60 has an output of 169,000, but it costs $5,375 at pexsupply. The Alpine 210 is $2,495 from the gas company. I can't justify the extra $3000 cost.

CMadatMe

Huh?

That price on the Alpine must be after rebates. What utlity and where? I know what an Alpine costs and the Vitodens and there is not that great of a difference.

JeffGuy

Pre rebate for both

This is before rebate. National Grid (MA) seems to have a special deal with Burnham and seems to be pushing hard to get customers to install Burnham . NOTE: this price is ONLY for an oil to gas conversion. They offer a similar rebate on non-Burnham, but they don't discount the price like they do with Burnham. See the link here: https://www.powerofaction.com/media/pdf/MA_EOF_writable.pdf



I can't tell you how many plumbers I talked to who would only install their own favorite boiler - but that was a non-starter for me because of the price difference.

CMadatMe

Mass Rebate

I know how the Mass rebate works as I have 2 Branches in Mass. The rebate is for all boilers.



95% gets you a $1,000.00 rebate

96% gets you a $1,500.00 rebate

Indirect for DHW gets you $400.00



If that Alpines AFUE label says 95% you only get the $1,000 bucks. That Vitodens is 96%. The Alpine was just recertified to 96%. That doesn't mean prior stock is and AFUE lables cannot be changed once put on an appliance. Its against Federal law.



What does upcharge mean?

JeffGuy

Model number?

Do you know if the Alpine has the same model number when they changed the efficiency labeling (it's ALP210W-2LO2 now)? I ordered it from the gas company today, so I hope/assume I'll get the newer label.



In any case, that would be only $500 out of the $3000 difference. Unless maybe pexsupply charges much more than other suppliers?

CMadatMe

Old

Nomenclature. New nomenclature would be ALP210W2T02 or ALP210W2G02. The T means Taco pump the G mean Grundfoss pumps. All new 96% Alpines come with pumps with the exception the 399 and 500. Your model is the old number the L means less pump which means 95% version. They may have just not updated their system but I would ask.

JeffGuy

Asking the gas company ...

Thanks, that's very helpful. Unfortunately the only way I could get them to talk to me was to go into their office and wait in the waiting room - and then they called me on my cellphone (even though I had left a message two and three days before asking for a call). But its worth another trip to try to pin this down.