EAST MILLINOCKET – Steve Gardner had his new Black Bear boiler at his house on Spring Street for about a month last fall when he noticed problems.

The 90,000-Btu outdoor wood-fired boiler would make a loud popping noise, as if its fire were restarting, even when it was burning well, he said Tuesday.

The Lincoln Unicel store owner worried that spending $7,500 on the boiler was a mistake, but repairmen from manufacturer Clean Wood Heat LLC of East Millinocket adjusted the boiler’s damper door and opened the bottom of the boiler to increase its airflow, he said.

“Now it’s running just fine,” Gardner said Tuesday. “It lights fine and it keeps the house heated, that’s for sure. Right now I am not running it really hard as far as loading it right up goes, but there’s no popping. It seems to be doing good.”

Glitches such as Gardner’s were part of the learning curve Clean Wood endured as it has tried to go from a handmade to assembly-line manufacturer, company co-owner Jeffrey W. Baker said Tuesday.

Many of the first 30 models it sold needed quality-control modifications and a cash-flow shortage forced Baker to shut down his company for about a month and a half since early January.

“Boy, nothing beats a real-world test,” he said.

“We had air and bypass damper issues to overcome and had restart problems,” he added, “but we’ve overcome the design flaws and worked well enough with the customers so that I’d say that out of the 30 original customers, 25-plus are satisfied.”

So, apparently, are Machias Savings Bank and Coastal Enterprises Inc. of Wiscasset, a private, nonprofit community development corporation and community development financial institution that provides financing for small businesses and natural resources industries.

Both are due today to loan Clean Wood a total of $450,000, including a $250,000 line of credit from the Machias bank, which will allow Baker to restart his company within the next two weeks, he said.

Christopher Fitzpatrick, a regional vice president at Machias Savings Bank, confirmed the pending loan but would not comment further, citing customer privacy issues. Al Moroney, a loan and investment officer at CEI, did not immediately return messages seeking comment Tuesday.

Baker and boiler inventor Dominic Federico hope to have about 20 full-time workers running one assembly line and manning Black Bear offices in the Katahdin Regional Industrial Park off Route 157 by May 1.

“We will be starting with eight to 10 people on the floor and three office people and going from there,” Baker said. “We told everybody we had to lay off to rest up because when we get back to work, it’s going to be all business. We have a lot of work to do. Everybody’s got their work cut out for them.”

Federico and Baker want 60 full-time workers producing 1,500 to 2,000 boilers at 2 Dirigo Drive by the end of 2008, they said. This is good news for the Katahdin region, which typically has unemployment double the state average and almost half its population at or below the poverty line.

The Black Bear’s performance and potential were enough to get the company a $10,000 grant late last year from the Maine Technology Institute, a state-funded, private nonprofit organization in Gardiner.

Of 52 applicants, the company was among 14 winners of seed money grants examined by nine volunteer reviewers representing the state’s forestry, biotech, information technology, composite materials, precision manufacturing, environmental and aquaculture sectors.

MTI awarded the grant because the Black Bear boiler is environmentally friendly. Most outdoor wood-fired boilers produce 25 to 111 grams of solid particulate waste an hour.

By comparison, most wood-fired stoves today produce about 7.5 grams an hour. U.S. Environmental Protection Agency guidelines encourage 24 to 37 grams an hour from wood-fired boilers.

The Black Bear emits 6.55 grams an hour, according to its Web site, blackbearboilers.com.

That’s good enough to comply with pending federal EPA standards for 2007 and 2008 as well as pass any local ordinance standards, Baker said.

Gardner also believes in the boiler, he said.

“I like it. I think they had a learning curve to go through. I have a lot of faith in it myself,” Gardner said. “All I know is that when it burns, you can’t see smoke coming out of it. It burns clean.”